Apparatus for low latency transmissions

ABSTRACT

An apparatus can include an antenna. The apparatus can include a transceiver coupled to the antenna, the transceiver configured to receive a resource assignment indicating a first set of time-frequency resources associated with a first subframe, the transceiver configured to receive a marker signal from higher layer signaling in a second subframe immediately following the first subframe, where the higher layer signaling indicates a set of orthogonal frequency multiplexed symbols including time-frequency resources used for a second latency data transmission. The apparatus can include a controller coupled to the transceiver, the controller configured to determine the first set of time-frequency resources in the first subframe from the resource assignment, the controller configured to determine a second set of time-frequency resources in the first subframe, and the controller configured to decode a first latency data transmission in the first subframe based on the determined first and second set of time-frequency resources.

BACKGROUND 1. Field

The present disclosure is directed to an apparatus and method for lowlatency transmissions. More particularly, the present disclosure isdirected to wireless transmissions, signaling, and frame structures fordevices configured for low latency data packets while maintainingbackward compatibility with devices configured for normal latency datapackets.

2. Introduction

Presently, users use wireless communication devices, otherwise known asUser Equipment (UE), such as smartphones, cell phones, tablet computers,selective call receivers, and other wireless communication devices, onLong Term Evolution (LTE) networks, Wireless Local Area Networks(WLANs), and other wireless communication networks. Users use thedevices to download files, music, e-mail messages, and other data, aswell as to watch streaming video, play streaming music, play games, surfthe web, and engage in other data intensive activities.

Packet data latency is one of the performance metrics widely used tobenchmark system performance. Packet data latency is important not onlyfor the perceived responsiveness of the system; it is also a parameterthat indirectly influences the throughput. Certain traffic types arelatency sensitive and require reduced latency for their data packets.Such latency sensitive traffic types can include Voice over InternetProtocol, such as for telephone calls, can include gaming, can includeautomobile control signals, and can include other time sensitive traffictypes. HTTP/TCP is the dominating application and transport layerprotocol suite used on the internet today with the TCP slow start periodis a significant part of the total transport period of the packetstream. During TCP slow start the performance is latency limited. Hence,improved latency can improve the average throughput, for this type ofTCP-based data transactions. The latency sensitive traffic types requiredownlink and uplink packet latency reduction, such as reduction in thetime taken for a device in connected mode to transmit and receive dataand signals. This is opposed to normal latency packets that are used fortraffic types like file downloading and uploading, which are lesslatency sensitive because the latency minimally affects the filetransfers and the normal latency is not readily apparent to a user.

In order to support the latency sensitive traffic types and otherlatency sensitive new use cases, to expand the application of LTE andother wireless communication systems to a wider set of scenarios, and toenhance LTE with better user perceived experiences there is a need tosupport lower latency through enhancement of LTE and other wirelesscommunication systems. Unfortunately, present devices do not adequatelyprovide a structure for low latency transmissions. Thus, there is a needfor a method and apparatus for low latency transmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of thedisclosure can be obtained, a description of the disclosure is renderedby reference to specific embodiments thereof which are illustrated inthe appended drawings. These drawings depict only example embodiments ofthe disclosure and are not therefore to be considered to be limiting ofits scope.

FIG. 1 is an example illustration of a system according to a possibleembodiment;

FIG. 2 is an example illustration of subframes according to a possibleembodiment;

FIG. 3 is an example illustration of a subframe according to a possibleembodiment;

FIG. 4 is an example illustration of an orthogonal frequency multiplexedsymbol according to a possible embodiment;

FIG. 5 is an example illustration of a transmission time intervalaccording to a related embodiment;

FIG. 6 is an example illustration of a transport block according to apossible embodiment;

FIG. 7 is an example illustration of a transport block according to apossible embodiment;

FIG. 8 is an example illustration of a transport block according to apossible embodiment;

FIG. 9 is an example illustration of a subframe according to a possibleembodiment;

FIG. 10 is an example illustration of a subframe according to a possibleembodiment;

FIG. 11 is an example illustration of a subframe according to a possibleembodiment;

FIG. 12 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment;

FIG. 13 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment;

FIG. 14 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment;

FIG. 15 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment;

FIG. 16 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment;

FIG. 17 is an example block diagram of an apparatus according to apossible embodiment;

FIG. 18 is an example block diagram of a device according to a possibleembodiment;

FIG. 19 is an example illustration of a subframe according to a possibleembodiment;

FIG. 20 is an example illustration of a subframe according to a possibleembodiment;

FIG. 21 is an example illustration of subframes according to a possibleembodiment;

FIG. 22 is an example illustration of a subframe according to a possibleembodiment;

FIG. 23 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment; and

FIG. 24 is an example flowchart illustrating the operation of a deviceaccording to a possible embodiment.

DETAILED DESCRIPTION

Embodiments can provide for a method and apparatus for low latencytransmissions.

According to a possible embodiment, a higher layer configuration messagecan be received. A first region of a subframe for receiving data packetscan be determined based on the higher layer configuration message. Thefirst region can include a first set of resource elements. The first setof resource elements can be a subset of a second set of resourceelements in the first region. The first region can be used for controlchannel monitoring. The data packets can be mapped to at least oneresource element of the first set of resource elements. The first regioncan be monitored by attempting to decode the data packets in the firstregion. Data in the data packet in the first region can be decoded.

According to another possible embodiment, a higher layer configurationmessage can be received that indicates a set of resource blocks forreceiving data packets in at least one symbol of a subframe. In anotherembodiment, the higher layer configuration message can indicate whichtime frequency resources are likely candidates for the transmission oflow latency related transmissions. The low latency related transmissionscan include, low latency data, low latency decoding assistanceinformation, and other low latency transmissions. An attempt can be madeto decode a data packet in a first set of resource elements within theset of resource blocks. The first set of resource elements can be in theat least one symbol of the subframe. An attempt can be made to decodethe data packet in at least a second set of resource elements within theset of resource blocks. The second set of resource elements can be inthe at least one symbol of the subframe. The second set of resourceelements can include at least one resource element that is not in thefirst set of resource elements. The data packet in one of the first setof resource elements and the second set of resource elements can besuccessfully decoded. A data payload of the decoded data packet can bedelivered to an application layer.

According to another possible embodiment, a higher layer configurationcan be received at a device. The higher layer configuration can behigher than a physical layer configuration. The higher layerconfiguration can indicate configuring the device with a low latencyconfiguration for a low latency transmission mode in addition to aregular latency configuration for a regular latency transmission mode.The low latency transmission mode can have a shorter latency than theregular latency transmission mode. A packet can be received based on oneof the low latency configuration and the regular latency transmissionmode in a subframe n. A feedback packet can be transmitted in afollowing subframe n+p, where p<4 when the received packet is based onthe low latency configuration, where the following subframe n+p can bethe p^(th) subframe from the subframe n. A feedback packet can betransmitted in a following subframe n+4 when the received packet isbased on the regular latency configuration, where the following subframen+4 can be the fourth subframe from the subframe n.

According to another possible embodiment, a resource assignment can betransmitted. The resource assignment can assign a first set oftime-frequency resources in a subframe for regular latency datatransmission. Low latency data can be transmitted within a second set oftime-frequency resources in the subframe. The second set can at leastpartially overlap with the first set. The low latency data can have alower latency than regular latency data. A marker signal can betransmitted. The marker signal can indicate a presence of low latencydata transmission in the subframe.

According to another possible embodiment, a resource assignment can bereceived. A first set of time-frequency resources in a subframe can bedetermined from the resource assignment. A second set of time-frequencyresources in the subframe can be determined. The second set oftime-frequency resources can be for a low latency data transmission. Thesecond set of time-frequency resources can overlap with at least aportion of the first set of time-frequency resources. A regular latencydata transmission in the subframe can be decoded based on the determinedfirst and second set of time-frequency resources. The regular latencytransmission can have a longer latency than the low latencytransmission.

According to another possible embodiment, a first control channel can betransmitted in a first temporal portion of a subframe. The subframe caninclude a plurality of Orthogonal Frequency Division Multiplexing (OFDM)symbols in a time domain and a plurality of subcarriers in a frequencydomain. The first control channel can occupy a first portion ofsubcarriers less than the plurality of subcarriers. The first controlchannel can assign first data resources only in the first temporalportion of the subframe. A second control channel can be transmitted ina second temporal portion of a subframe. The first temporal portion canoccupy at least one different first OFDM symbol in the subframe from thesecond temporal portion. The second temporal portion can occupy at leastone different second OFDM symbol in the subframe from the first temporalportion. The second control channel can occupy a second portion ofsubcarriers that is less than the plurality of subcarriers. The secondcontrol channel can assign second data resources only in the secondtemporal portion of the subframe.

According to another possible embodiment, a first control channel can bemonitored in a first temporal portion of a subframe. The subframe caninclude a plurality of Orthogonal Frequency Division Multiplexing (OFDM)symbols in a time domain and a plurality of subcarriers in a frequencydomain. The first control channel can occupy a first portion ofsubcarriers less than the plurality of subcarriers. The first controlchannel can assign data resources only in the first temporal portion ofthe subframe. A second control channel can be monitored in a secondtemporal portion of a subframe. The first temporal portion can occupy atleast one different OFDM symbol in the subframe from the second temporalportion. The second temporal portion can occupy at least one differentOFDM symbol in the subframe from the first temporal portion. The secondcontrol channel can occupy a second portion of subcarriers less than theplurality of subcarriers. The second control channel can assign dataresources only in the second temporal portion of the subframe. The firstcontrol channel can be decoded. In response to decoding the firstcontrol channel, data can be received in the first temporal portion ofthe subframe. The data in the first temporal portion can be assigned bythe first control channel The data can be decoded.

According to some embodiments, in order to support new use cases andexpand the application of Long Term Evolution (LTE) and other wirelesscommunications to a wider set of scenarios, and to enhance LTE withbetter user perceived experiences there is a need to support lowerlatency through enhancement of LTE. Embodiments can provide a new framestructure and other features to support devices needing lower latencywhile at the same time supporting devices with regular latency.

FIG. 1 is an example illustration of a system 100 according to apossible embodiment. The system 100 can include a first device 110 and asecond device 120. While the first device 110 is illustrated as a UserEquipment (UE) and the second device 120 is illustrated as a basestation, such as an Enhanced Node-B (eNB), the roles may also bereversed. Furthermore, the devices 110 and 120 can be the same type ofdevice, such as UE's or base stations, and can be any other type ofdevice that can send and receive wireless communication signals. Forillustrative purposes in some embodiments, the first device 110 may bereferred to as a UE and the second device 120 may be referred to as abase station, but it is understood that the first device and the seconddevice 120 can be any transmitting and/or receiving devices in all ofthe embodiments. The first device 110 and the second device 120 cancommunicate on different cells 130 and 140. The system 100 can alsoinclude another device 112 that can communicate with the second device120 on different cells 132 and 142 in a similar manner to the firstdevice 110. The devices 110 and 112 can be any devices that can access awireless network. For example, the devices 110 and 112 can be UE's, suchas wireless terminals, portable wireless communication devices,stationary wireless communication devices, smartphones, cellulartelephones, flip phones, personal digital assistants, personal computershaving cellular network access cards, selective call receivers, tabletcomputers, or any other devices that are capable of operating on awireless network.

The communication system 100 can utilize Orthogonal Frequency DivisionMultiple Access (OFDMA) or a next generation single-carrier based FDMAarchitecture for uplink transmissions, such as interleaved FDMA (IFDMA),Localized FDMA (LFDMA), Discrete Fourier Transform -spread OFDM(DFT-SOFDM) with IFDMA or LFDMA. In other embodiments, the architecturemay also include the use of spreading techniques such as direct-sequenceCDMA (DS-CDMA), multi-carrier CDMA (MC-CDMA), multi-carrier directsequence CDMA (MC-DS-CDMA), Orthogonal Frequency and Code DivisionMultiplexing (OFCDM) with one or two dimensional spreading, or simplertime and frequency division multiplexing/multiple access techniques. Inanother implementation, the wireless communication system is compliantwith the 3GPP Universal Mobile Telecommunications System (UMTS) LTEprotocol, also referred to as EUTRA or some later generation thereof,wherein the base unit transmits using an orthogonal frequency divisionmultiplexing (OFDM) modulation scheme on the downlink and the userterminals transmit on the uplink using a single carrier frequencydivision multiple access (SC-FDMA) scheme. In yet anotherimplementation, the wireless communication system is compliant with the3GPP Universal Mobile Telecommunications System (UMTS) LTE-Advancedprotocol, also referred to as LTE-A or some later generation or releaseof LTE thereof, wherein the base unit can transmit using an orthogonalfrequency division multiplexing (OFDM) modulation scheme on a single ora plurality of downlink component carriers and the user terminals cantransmit on the uplink using a single or plurality of uplink componentcarriers. More generally the wireless communication system may implementsome other open or proprietary communication protocol, for example,WiMAX, among other existing and future protocols. The architecture inwhich the features of the embodiments are implemented may also be basedon simpler time and/or frequency division and/or space divisionmultiplexing/multiple access techniques, or a combination of thesevarious techniques. In alternate embodiments, the wireless communicationsystem may utilize other communication system protocols including, butnot limited to, Time Division Multiple Access (TDMA) or direct sequenceCode Division Multiple Access (CDMA). The communication system may be aTime Division Duplex (TDD) or Frequency Division Duplex (FDD) system.

In OFDM systems or OFDM like systems such as DFT-SOFDM and IFDMA, aresource allocation is a frequency and time allocation that mapsinformation for a particular communication device or remote unit tosub-carrier resources from a set of available sub-carriers as determinedby a scheduler. This allocation may depend, for example, on thefrequency-selective Channel-Quality Indication (CQI) or some othermetric reported by a remote unit, such as a user equipment, to thescheduler. The channel-coding rate and the modulation scheme, which maybe different for different portions of the sub-carrier resources, arealso determined by the scheduler and may also depend on the reported CQIor other metric. In code division multiplexed networks, the resourceallocation is code allocation that maps information for a particularcommunication device or remote unit to channelization code resourcesfrom a set of available channelization codes as determined by thescheduler.

In LTE, the radio frame can generally comprise a plurality of subframes,which may form a concatenated continuum of subframes. An example radioframe contains 10 subframes. Each subframe can correspond to aTransmission Time Interval (TTI). An example TTI is 1 ms. Each subframecan be composed of two slots each having a 0.5 ms length with each slotcontaining for example, 7 OFDM symbols given a normal cyclic prefixlength and only 6 OFDM symbols if an extended cyclic prefix length isused. Each subframe can be composed of a control region and a dataregion. The control region may be in time-domain comprising one or moreOFDM symbols, or in frequency domain comprising one or more resourceblocks. In communication systems, assigned channels can be employed forsending data and also for control signaling or messaging of the system.Control signals or messages may be transmitted in Control CHannels(CCHs) and are used for both the forward link transmissions, also knownas the downlink transmission, from a network or base station to userequipment or device, and reverse link transmission, also known as uplinktransmissions, from the user equipment or device to the network or basestation. In systems, such as LTE of UTRA, where the downlink controlchannel is composed of a single decodable element called a ControlChannel Element (CCE), or an aggregation of decodable elements calledControl Channel Elements (CCEs), a user equipment can identify from alarge group of CCEs the subset of CCEs intended for the particular userequipment. In one embodiment the user equipment can be configured toattempt to decode low latency packets or messages transmitted in thecontrol region. The user equipment can be configured to monitor lowlatency packets in a subset of the CCEs, denoted as Low Latency CCEs(LL-CCEs) intended for possible low latency data transmissions to theuser equipment. The subset of CCEs intended for a particular userequipment to monitor or attempt to decode at a particular CCEaggregation level, L, (e.g., L=1, 2, 4 or 8 CCEs) is called the set ofresources for that user equipment at the particular CCE aggregationlevel, L. The set of resources for a user equipment can contain one ormore resource subsets where each resource subset can include one or moreCCEs corresponding to the aggregation level and the resource subset cancorrespond to a candidate downlink control channel also called aphysical downlink control channel (PDCCH) candidate. The set of resourcesubsets at a particular CCE aggregation level, L, can correspond to theset of PDCCH candidates at the aggregation level L that the particularuser equipment monitors in the search space corresponding to set ofresources at the particular CCE aggregation level, L. The control regionsize can be, for example, 1, 2, or 3 OFDM symbols and may depend on anumber of symbols signaled for a subframe in a higher layerconfiguration message or may depend on the number of symbols signaled bya Physical Control Format Indicator Channel (PCFICH) which can betransmitted in symbol 0 of each subframe control region and can becomposed of four Resource Element Groups (REGs) distributed acrossfrequency. Each REG can be composed of 4 contiguous or nearly contiguouscontrol resource elements and may also include up to 2 reference signalsif the associated antenna ports are configured. Each CCE can include 9REGs which can be pseudo-randomly distributed or interleaved acrossfrequency and the OFDM control symbols in the control region based on asubblock interleaver. The CCEs and corresponding REGs available to usefor low latency data transmissions, may be the remaining CCEs in thecontrol region after accounting for PCFICH and the Physical HybridAutomatic Repeat ReQuest (ARQ) Indicator CHannel (PHICH), and controlchannel CCEs. A Physical Downlink Control CHannel (PDCCH) can includefor example 1, 2, 4, or 8 CCEs depending on the CCE aggregation level,L. A PDCCH can be associated with a DCI format type. The PDCCH conveysDownlink Control Information (DCI) of a given DCI format type thatcontains the data assignments. Two or more DCI format types may have thesame DCI format size or may have different DCI format sizes. The numberof DCI format types assigned to a user equipment to monitor can bedependent on the transmission mode, such as downlink MIMO or downlinksingle antenna, assigned to the user equipment via higher layersignaling such as Radio Resource Control (RRC) signaling. In the casewhere more than 1 CCE is aggregated to form the PDCCH, the CCEs can bein logically contiguous in terms of the location in the PDCCH candidatesearch spaces. The PDCCH candidate locations may be the same for one ormore DCI format types. The data region can contain data symbols, such asQAM symbols with one data symbol per Resource Element (RE). Twelveconsecutive resource elements for a duration of a slot can be grouped toform resource blocks (RBs). A resource block can span a slot or 7 OFDMsymbols for a normal cyclic prefix length such that two RBs (or a singleRB pair) span the subframe. The number of data OFDM symbols in the firstRB corresponding to the first slot of a subframe can be shortened by thenumber of OFDM control symbols allocated. In one embodiment, the userequipment can attempt to decode control channel and low latency datatransmissions in the control region. The user equipment can identify acontrol channel based on a first RNTI (e.g., C-RNTI) and low latencydata packets based on a second RNTI (e.g., LL-RNTI). The set ofaggregation levels for low latency data packets candidates may be thesame, a subset, or different than the set of aggregation levels forPDCCH candidate the UE monitors. In some embodiments, for a particularaggregation level, the search space for the low latency data packets maybe the same as the search space for PDCCH. In other embodiments, for aparticular aggregation level, the search space for the low latency datapackets may be a subset or different (e.g., non-overlapping, partiallyoverlapping) than the search space for PDCCH. In some embodiments, for aparticular aggregation level, the search space for the low latency datapackets may be an offset from the search space for PDCCH. The offset maybe based on the number of PDCCH candidates at that particularaggregation level and the value of the particular aggregation level.Such an approach can prevent blocking when multiple uplink and/ormultiple downlink scheduling grants or assignments occur in the controlregion of a subframe. In some embodiments, one or more of the possiblelow latency data payload sizes associated with the monitored low latencydata packets candidates may be the same, a subset, or different than theDCI format sizes associated with the monitored PDCCH candidates. In oneembodiment, the user equipment may for a particular aggregation leveland candidate, first attempt to decode the control channel candidateusing its C-RNTI and failing this, it can attempt to decode using theLL-RNTI. Alternately, it can attempt to decode the candidate usingdifferent Downlink Control Information (DCI) format types with possiblydifferent DCI format sizes. In one further embodiment, a new DCI formattype can be defined for low latency transmissions or packets. The newDCI format type for low latency data packets may have a different DCIformat size than the DCI format size of PDCCH for regular latency datapackets. The DCI format type may also be referred to as control channelmessage type.

In one embodiment, some of the REs in the data region can be set asidefor supporting low latency transmissions. In one embodiment, the REs canbe used for low latency data packet transmission. In other embodimentsthe REs may also be used for marker information transmission to assistuser equipments receiving regular latency transmissions in decodingregular latency packet transmissions and/or low latency packettransmissions.

In some embodiments, a user equipment may monitor low latency controlchannel (e.g., LL-PDCCH) candidates with a DCI that contains theresource assignment for a low latency data packet. The low latency datapacket may be transmitted in a data region from one or more data regionsin a subframe. In an embodiment, the low latency data packet can betransmitted in a data region associated with or based on the location ofthe control channel that contains the resource assignment for the lowlatency data packet. The relationship between the location of the lowlatency data packet and the control channel containing the low latencydata resource assignment may be predetermined (e.g, each subframe regioncan include a control channel and low latency data region, the resourceelements or resource element groups of the control channel and lowlatency data region may be interleaved within the subframe region), ordetermined by higher layer signaling (e.g., signaling of one or moreconfiguration parameters, such as gap or offset, OFDM symbols, resourceblock indices etc.). In another embodiment, the location of the lowlatency data packet can be included in the DCI resource assignmentmessage of the control channel corresponding to the low latency datapacket for the user equipment. A particular user equipment can locatethe low latency control channel elements corresponding to each LL-PDCCHcandidate it is to monitor (blindly decode). The CRC of each LL-PDCCHcan be masked by a unique identifier corresponding to the user equipmentthat the base station is trying to schedule. The unique identifier canbe assigned to the UE by its serving base station. This identifier canbe known as a radio network temporary identifier (RNTI) and the onenormally assigned to each UE at call admission can be the cell RNTI orC-RNTI. A UE may also be assigned a Semi-Persistent-Scheduling C-RNTI(SPS C-RNTI) or a temporary C-RNTI (TC-RNTI) or a low latency RNTI(LL-RNTI). When a UE configured to receive low latency transmissiondecodes a LL-PDCCH it may, in addition to the C-RNTI (e.g., in case theLL-PDCCH can also be used for regular latency data packet assignment,with same DCI format size), also apply its LL-RNTI in the form of a maskto the PDCCH CRC for successful LL-PDCCH decoding to occur in case lowlatency transmission control channel has been transmitted to the userequipment. When a user equipment successfully decodes a LL-PDCCH of aparticular DCI format type with CRC masked with LL-RNTI, it can use thecontrol information from the decoded LL-PDCCH to determine, for example,the resource allocation, Hybrid ARQ information, and power controlinformation for the corresponding low latency data.

In LTE, DCI format type 0, 4 is used for scheduling uplink datatransmissions on the Physical Uplink Shared CHannel (PUSCH) and DCIformat type 1A is used for scheduling downlink data transmissions on thePhysical Downlink Shared CHannel (PDSCH). Other DCI format types arealso used for scheduling PDSCH transmissions including DCI format1,1B,1D,2,2A,2B,2C,2D, each corresponding to a different transmissionmode (e.g. single antenna transmissions, single user open loop MIMO,multi-user MIMO, single user close loop MIMO, rank-1 precoding, duallayer transmission scheme, up to 8 layer transmission scheme). Alsothere are DCI format 3 and 3A for scheduling the transmission of jointpower control information. PDCCH DCI format 0, 1A, 3, and 3A all havethe same size payload and hence the same coding rate. So only one blinddecoding is required for all of 0, 1A, 3, 3A per PDCCH candidate. TheCRC is then masked with C-RNTI to determine if the PDCCH was DCI formattype 0 or lA and a different RNTI if it is 3 or 3A. DCI format type 0and 1A are distinguished by DCI type bit in the PDCCH payload itself(i.e. part of the control information on one of the control informationfields). A UE may always be required to search for all of DCI formats 0,1A at each PDCCH candidate location in the UE specific search spaces.There are four UE specific search spaces for aggregation levels 1, 2, 4,and 8. Only one of the DCI format types 1, 1B, 1D, 2, 2A, 2B, 2C, or 2Dis assigned at a time to a UE such that a UE only needs to do oneadditional blind decoding per PDCCH candidate location in the UEspecific search space besides the blind decoding needed for the DCIformat types 0, 1A and possibly DCI format type 4. The PDCCH candidatelocations are the same for the DCI format types when they are located inthe UE specific search spaces. There are also two 16 CCE common searchspaces of aggregation level 4 and 8 respectively that are logically andsometimes physically (when there are 32 or more control channelelements) adjacent to the UE specific search spaces. In the commonsearch spaces, a UE monitors DCI types 0, 1A, 3, and 3A as well as DCIformat type 1C. DCI format type 1C is used for scheduling broadcastcontrol which includes paging, random access response, and systeminformation block transmissions. DCI 1A may also be used for broadcastcontrol in the common search spaces. DCI 0 and 1A are also used forscheduling PUSCH and PDSCH in common search spaces. A UE is required toperform up to 4 blind decodings in the L=4 common search space and 2blind decodings in the L=8 common search space for DCI formats 0,1A,3,and 3A and the same number again for DCI 1C since DCI 1C is not the samesize as DCI 0,1A,3and 3A.

A UE is required to perform (6, 6, 2, 2) blind decodings for L=(1, 2, 4,8) UE specific search spaces respectively where L refers to theaggregation level of the search space. The total maximum number of blinddecoding attempts a UE is then require to perform per subframe controlregion is therefore 44 (=2×(6,6,2,2)+2×(4,2)) for two DCI format sizesin the UE specific search space and two DCI format sizes in the commonsearch space. A hashing function is used by the base station and the UEto fmd the PDCCH candidate locations in each search space. The hashingfunction is based on the UE RNTI (identifier associated with theUE.e.g., C-RNTI, or Temporary C-RNTI), aggregation level (L), the totalnumber of CCEs available in the control region (Ncce), the subframenumber or index, and the maximum number of PDCCH candidates for thesearch space. Such an approach prevents blocking when multiple controlchannels and/or low latency data packets occur in the same region of asubframe.

In one embodiment, a method in a base station can indicate the lowlatency message resource subset corresponding to the low latencymessage, which can be selected by the base station from one of the oneor more candidate resource subsets in a search space within a control ordata region based on at least a low latency message type (e.g., LL xyzformat type) of the low latency message to a UE. The low latency messagetype may correspond to an identifier other than a PDCCH DCI format type.The UE can determine which set of resources in a search space to use forblind decoding attempts at least partially based upon one or more of alocation offset (in terms of number of CCEs or aggregated CCEs or interms of number of candidates at the aggregation level) associated withor determined by a low latency message type of the low latency messagethe UE is to search and an identifier associated with the UE. Each setof resources located in a search space therefore can include candidateresource subsets of a particular message type with a location offsetrelative to a set of resources with zero offset or relative to thelocation of a reference set of resources. Low latency messageinformation for the UE can be transmitted by the base station via theselected resource elements subsets using the selected resource subsetfrom the set of resources associated with the low latency message type.The UE can use blind decoding attempts to determine which resourcesubset was used from the set of resources in a search space forcommunicating the low latency message.

In one embodiment, a particular user equipment may locate the resourceelements corresponding to each low latency data channel candidate it isto monitor (blindly decode for each subframe control region). The CRC ofeach low latency data channel may be typically masked by a uniqueidentifier corresponding to the user equipment that the base unit istrying to schedule. In other embodiments the CRC may be masked with acommon identifier for all low latency data packets or low latency datapacket receiving user equipments. The unique identifier can be assignedto the UE by its serving base station. In one embodiment, thisidentifier can be known as a Radio Network Temporary Identifier (RNTI)and the one normally assigned to each UE at call admission can be theLow Latency RNTI or LL-RNTI. A UE may also be assigned asemi-persistent-scheduling C-RNTI (SPS C-RNTI) or a temporary C-RNTI(TC-RNTI) and a cell specific C-RNTI. When a UE decodes resourceelements corresponding to a low latency data packet, it can apply itsLL-RNTI in the form of a mask to the low latency data packet CRC forsuccessful decoding to occur. When a UE successfully decodes a lowlatency data packet meant for it, it can then send it to the applicationlayer for use by the appropriate service needing low latencytransmission. The UE may need to attempt to descramble the decodedpacket in order to determine that the packet is meant for it. In oneembodiment, all UE's can be capable of decoding the low latency packetsbut may not be able to read the contents of the packets if they fail todescramble the decoded packet successfully. The scrambling process bythe base station prior to transmission allows the base station tomaintain user privacy while permitting every user equipment to decodethe packet.

Channel coding (e.g., convolutional coding) blind detection can be usedto distinguish between PDCCH DCI formats with different sizes. For DCIformats of the same size, different masking of the scrambled CRC can beused or instead an extra bit in the PDCCH payload itself can be used todistinguish between same size PDCCH DCI formats (e.g. DCI format 0 and1A). An example includes, but is not limited to, the case of broadcastcontrol which uses SI-RNTI, P-RNTI, or RA-RNTI for DCI format 1A insteadof C-RNTI.

In one embodiment, the UE search space may support 4 aggregation levelsincluding (1, 2, 4, or 8) logically contiguous CCEs per PDCCH(candidate) hypothesis and low latency data candidates with (6,6,2,2)blind detection locations, for each of the aggregation levelsrespectively.

In one method of determining the CCE locations S_(k) ^((L))corresponding to a PDCCH or low latency data candidate m of eachaggregation level L (e.g., L=(1, 2, 4, or 8)) search space for subframe‘k’ of a radio frame is given by equation:

S _(k) ^((L)) =L{(Y _(k) +m′)mod(└N _(CCE,k) /L┘)}+i   (1)

where Y_(k)=39827·Y_(k−1) mod 65537 where Y⁻¹=n_RNTI for the UE specificsearch space; n_RNTI≠0 is either C-RNTI or temporary C-RNTI or LL-RNTI;N_(CCE,k) is the number of total CCEs available for subframe k; m′=m forPDCCH candidates; and m′=m+Δ(M^((L))) for low latency data candidates,where Δ is an offset based on the number of PDCCH candidates to monitorin the search space at aggregation level L (M^((L))). For example,Δ=αM^((L)), where α can take on values such as ⅓, ½, 1, m=0, . . . ,M^((L))−1, where M^((L))=(6,6,2,2) for L=(1,2,4,8), and i=0, . . . ,L−1where i spans each consecutive CCE of the PDCCH or low latency datahypothesis.

Equation (1) can randomize the candidate hypothesis CCE locations peraggregation level search space to minimize blocking. A UE can performs aconvolutional coding blind detection (CCBD) for DCI format types forPDCCH and low latency data at the corresponding aggregation level forthe candidate hypothesis. The blind decoding can allow the base stationto dynamically select the aggregation size based on for example thechannel conditions such that a large number of CCEs need not be used allof the time.

FIG. 2 is an example illustration 200 of subframes n through n+4according to a possible embodiment. The subframe n can include a firstregion 210, such as a control region, and a second region 220, such as adata region. The first region 210 can include resource elements 230. Insome embodiments, a resource element (RE) can represent a singlesubcarrier for a single OFDM symbol period in the subframe. Moregenerally, a resource element can be a smallest identifiabletime/frequency/code/spatial domain resource unit within the subframe.Data packets, such as low latency data packets or other data packets,can be mapped to at least one resource element of the resource elements230. If a data packet is received in the first region 210, anacknowledgement, such as a HARQ ACK, can be sent in a subsequentsubframe, such as a subframe earlier than subframe n+4, that issubsequent to the subframe n in which the data packet is received.

According to this possible embodiment, a device can receive a higherlayer configuration message, where the higher layer can be higher than aphysical layer. The higher layer message can be a dedicated mode RRC(Radio Resource Control) message sent to the device. In some embodimentsit can be sent through broadcast system information message to alldevices in a cell. The device can determine, based on the higher layerconfiguration message, a first region of a subframe for receiving datapackets. In one embodiment the first region in the subframe cancorrespond to a set of time-domain resources in the subframe, such asOFDM symbols durations. In another embodiment the first region of thesubframe can correspond to a set of frequency-domain resources in thesubframe such as Resource Blocks (RBs) where each resource block cancomprise a set of OFDM sub-carriers. In another embodiment the firstregion of the subframe can correspond to a set of Resource Elements(REs). In yet another embodiment the first region of the subframe cancorrespond to a set of Control Channel Elements (CCEs), where eachcontrol channel element can correspond to a set of resource elements orset of Resource Element Groups (REGs) within the subframe. The firstregion can include a first set of REs, where the first set of REs can bea subset of a second set of REs in the first region. In someembodiments, the second set of resource elements can correspond to allthe resource elements in the first region of the subframe on which thedevice can expect to receive control channels. The control channels canbe channels such a Physical Downlink Control Channel (PDCCH) or EnhancedPhysical Downlink Control Channel (EPDCCH). In some other embodiments,the second set of resource elements can correspond to all the resourceelements in the first region of the subframe on which the device canexpect to receive control channels and acknowledgement signalling. Thecontrol channels can be channels such as PDCCH and EPDCCH. Theacknowledgement signalling can be channels, such as Physical Hybrid-ARQIndicator Channel (PHICH). In some other embodiments, the second set ofresource elements can correspond to all the resource elements in thefirst region of the subframe. The first region can be used for controlchannel monitoring. Data packets can be mapped to (or transmitted on) atleast one RE of the first set of REs. The device can monitor the firstregion, where monitoring can include attempting to decode the datapackets in the first region. Attempting to decode can include blinddecoding by the device. The device can decode data in the data packet inthe first region. In one embodiment, the device can monitor the firstset of REs in the first region, where monitoring can include attemptingto decode the data packets in the first set of REs first region.Attempting to decode can include blind decoding by the device. Thedevice can decode at least one data packet in at least some REs of thefirst set of REs in the first region.

In some embodiments, the higher layer message can include a list ofpossible candidate resource elements or REGs, also used as controlchannel elements, that the device can attempt to receive low latencydata on. The base station can set aside a set of REGs for low latencytransmission but these REGs can be available to be reused for PDCCHtransmission in case there is no low latency data to be transmitted orif other scheduling priorities do not permit transmission of low latencydata in that subframe.

In some embodiments the device can monitor the second set of REs in thefirst region of the subframe for control channel signalling and alsomonitor the first set of REs, which can be a subset of the second set ofREs, for low latency data packet transmissions. Both the first andsecond set of REs can belong to the first region of the subframe. Thefirst region can be a control region of the subframe. As a result of themonitoring, if the device decodes control signalling in the first regionof the subframe, the device can use the downlink control information(DCI) to determine PDSCH resource assignments. The PDSCH resourceassignments can be used by the device to receive payload of data packets(e.g. regular latency data packets), which can then be delivered tohigher layers such as an application layer. As a result of themonitoring, if the device decodes payload of low latency data packets inthe first region of the subframe, the device can deliver the low latencydata packets to higher layers such as an application layer. Low latencydata packets can have more stringent packets delivery delay requirementsthan regular latency data packets.

According to a related implementation, the device can be configured viahigher layer signalling to monitor for low latency (LL) data packetswith a low latency Downlink Control Information (DCI) format (e.g. a DCIFormat LL1). The low latency DCI format can also be alternativelyreferred to as Low latency Data Information format (LDI format). Thedevice may also be configured with higher layers with transmission modeand, based on the transmission mode, the device may monitor controlsignalling that assigns PDSCH data assignments using transmission of oneor more DCI formats (e.g. DCI format 1A,1,2,2A,2B,2C). The device maymonitor for low latency data packets with the low latency DCI format inthe control region of the subframe. Up to three or more OFDM symbols canbe used for the control region. Alternately, up to 8 or more RBs in thesubframe can be used for control region.

FIG. 19 is an example illustration of a subframe 1900 according to apossible implementation of this embodiment. The subframe 1900 caninclude a first region 1910, such as a control region, and a secondregion 1920, such as a data region. The first set of REs used for LLdata monitoring can be further organized into multiple control channelelements (CCEs) 1930 and 1940 where each CCE 1930 and 1940 can includemultiple resource elements. The device may monitor the same controlchannel elements (CCEs) in the control region for both low latency dataand for control signalling that assigns PDSCH data assignments. Moregenerally, the device may monitor a first set of CCEs created byorganizing the first set of REs for low latency data assuming a firstDCI format (e.g. DCI format LL1) and first set of CCE aggregationlevels, and a second set of CCEs created by organizing the second set ofREs for control channels that assign PDCCH data assignments assuming asecond DCI format (e.g. DCI Format 1A,1,2,2A, 2B,2C) and a second set ofCCE aggregation levels. Monitoring can be attempting to decode eitherlow latency data or control channels according to the assumed DCIformat(s) and aggregation level(s). ‘Monitoring’ or ‘attempting todecode’ can also be blind decoding. The first set of CCEs can be asubset of the second set of CCEs. Alternately, the first set of CCEs canbe same as second set of CCEs. Having the first set as a subset of thesecond set can reduce the blind decoding complexity for the device.Similarly, the first set of CCE aggregation levels can be same as secondset of CCE aggregation levels or the first set of CCE aggregation levelscan be a subset of second set of CCE aggregation levels, such asaggregation levels L=2,4,8 for monitoring LL data transmissions andL=1,2,4,8 for monitoring control channels. Having fewer aggregationlevels for monitoring LL data packets can also reduce UE blind decodingcomplexity. The CCE size used for monitoring LL data packets can bedifferent from the CCE size used for monitoring control channels. Forexample, for monitoring LL data, a CCE size of 72 REs (or 18 REGs whereeach REG has 4 data REs) can be used while, for monitoring controlchannels, a CCE size of 36 REs (or 9 REGs where each REG has 4 data REs)can be used. The DCI format size(s) of the low latency DCI format(s) canbe same as one of the DCI format sizes used for control channelmonitoring. For example, DCI format LL1 can be same size as DCI Format1A, and DCI Format LL2 can be same size as one of the transmission modespecific DCI formats. For example, if the device is configured withtransmission mode 2, DCI Format LL2 will have same size as DCI Format 1,if the device is configured with transmission mode 10, DCI Format LL2will have same size as DCI Format 2D. Transmission of data in thecontrol region is especially suitable for small data packet sizes, suchas 8-500 bits.

In some implementations, the LL data information (LDI or LL DCI)monitored in the first region can be distinguished from the DCI of thecontrol channels monitored in the same region based on Cyclic RedundancyCheck (CRC) masking with different CRC masks. This is especiallysuitable when the DCI format size(s) of the low latency DCI format(s)are same as one of the DCI format sizes used for control channelmonitoring. During blind decoding (or monitoring) of control channelsfor DCI that contains PDSCH data assignments, the device may assume thatthe CRC of the DCI is encoded or scrambled with a device specificidentifier, for example a Cell-Radio Network Temporary Identifier(C-RNTI); or a common identifier, for example a Paging-Radio NetworkTemporary Identifier (P-RNTI). During blind decoding (or monitoring) ofLL data packets, the device may assume that the CRC of the payload ofthe LL data packet is encoded with a special identifier associated withLL data monitoring, for example a Low Latency -Radio Network TemporaryIdentifier (LL-RNTI). The special identifier can be indicated to thedevice via higher layer (e.g, RRC) messages. More generally, the devicecan perform control channel monitoring in a first region of a subframe,the device can determine successful decoding of a control channel (e.g.PDCCH) or the DCI associated with the control channel using a firstidentifier (e.g. using a cyclic redundancy check (CRC), assuming thatthe CRC of the DCI is encoded using C-RNTI), and the device candetermine successful decoding of data payload of a data packet (e.g. aLL data packet) in the first region using a second identifier (e.g.using a cyclic redundancy check (CRC), assuming that the CRC of the datapayload is encoded using LL-RNTI)

The CCEs or groups of REs from the second set of REs monitored by thedevice for control signalling can be associated with control channelssuch as PDCCH or EPDCCH. In some implementations, the CCEs or groups ofREs in the first set monitored by the device for LL data can beassociated with a separate physical channel using which low latency datais received (e.g. LL-PDSCH). In some cases, groups of REs in the firstset monitored by the device for LL data can be referred by a name otherthan ‘CCEs’ such as Low latency Channel Elements (LCEs). In someimplementations, the CCEs monitored by the device for LL Data can stillbe associated with a control channel such as PDCCH or EPDCCH, but theinformation decoded on the CCEs, i.e., the DCI or LDI, is associatedwith a data channel such as PDSCH.

In some implementations, feedback (e.g. ACK or NACK) in response todecoding LL data can be sent in a subframe earlier than subframe n+4,such as subframe n+2, in response to LL data packets decoded in thefirst region of a subframe n. In this implementation, a device may beconfigured via higher layers with a low-latency transmission mode or alow-latency feature. The first region can be a control regioncorresponding to the first 1-3 OFDM symbols of a lms TTI. Since theregion is in the beginning portion of the subframe, the LL data sentthere can be decoded much earlier. For example, the decoding can startwhen the device receives 3 OFDM symbols (if the LL data is sent incontrol region) rather than after device receives all 14 OFDM symbols(if the LL data were to be sent in regular manner, such as using PDSCHRBs that span till the end of the subframe that are assigned via DCI inPDCCH/EPDCCH) of a lms TTI. Due to this early decoding benefit, thedevice can then transmit the feedback earlier, such as in subframe n+2,or in latter half of subframe n+1. If the payload for LL data is small,such as around 100 bits or so the control channel decoder implemented indevices can also take advantage of the smaller payload to complete thedecoding early.

According to a possible implementation, a first region, such as acontrol channel region of a LTE subframe, can be used to define a newresource allocation design in support of low latency packet transmissionand can be used for a control channel for normal or regular latencypacket transmission. The device can be configured with a first set ofRE's within the control channel region and the device can then blindlydecode data packets using this first set of RE's. Downlink latency canbe reduced in multiple ways in conjunction with a legacy framestructure, such as the LTE Rel-8 frame structure, where a legacyTransmission Time Interval (TTI) can have a lms duration, the legacysubframe can be lms, and a legacy slot can be 0.5 ms. The system 100 canbe simultaneously run with at least two different TTI durations, alegacy 1 ms TTI duration and at least one new TTI duration, such as 0.5ms. Embodiments can provide faster processing time and faster HybridAutomatic Repeat Request (HARQ) feedback transmission, such as where aHARQ Acknowledgement (HARQ-ACK) can be sent faster than 4 TTI's later,such as earlier than subframe n+4 after subframe n. For example, anACK/NACK can be sent in subframe n+2, instead of n+4. Embodiments canalso provide for faster Channel Quality Indicator (CQI) transmission,reduced TTI duration for packet transmission, such as using 0.5 ms TTI,and reduced TTI duration for feedback transmission, such as using 0.5 msTTI. For Time Division Duplex (TDD), for a Physical Downlink SharedChannel (PDSCH) in subframe n, an uplink ACK/NACK resource can beassigned in each n+2 or n+4 timing.

In LTE, in the downlink, a UE may be configured with a transmission modefrom a plurality of transmission modes for PDSCH reception, such astransmission mode 1-10 in Rel-12 LTE. A transmission mode can beassociated with one or more PDSCH transmission scheme. A PDSCHtransmission scheme may be, for example, a single antenna porttransmission, transmit diversity, closed loop spatial multiplexing, openloop spatial multiplexing, large delay cyclic delay diversity, dual or aplurality of antenna ports transmission schemes. Some transmissionschemes support transmission of only a single transport block in a TTI(such as a subframe), while some other transmission scheme support up totwo transport blocks in a TTI. The reference signal or pilot signalassociated with a transmission scheme for PDSCH demodulation may be aCommon Reference Signal (CRS) or a UE-specific or dedicated DeModulationReference Signal (DM-RS). A transmission scheme may be associated with aDownlink Control Information (DCI) format of a given payload size whichincludes the resource assignment and other control information fordecoding the PDSCH. The DCI format may be transmitted on a PDCCH(Physical Downlink Control Channel) or an EPDCCH (Enhanced PDCCH) whichincludes CRC (Cyclic Redundancy Check) bits which may be scrambled by aparticular C-RNTI configured for the device Similarly, on the uplink, aUE may be configured a transmission mode from a plurality oftransmission modes for PUSCH (Physical Uplink Shared Channel)transmission, such as transmission mode 1-2 in Rel-12 LTE. The PUSCHtransmission schemes may include single antenna port and closed loopspatial multiplexing transmission schemes.

In one embodiment, a device can be configured with a low-latencytransmission mode, such as a low latency downlink control informationformat where transmission (Tx) HARQ ACK can be sent in subframe n+2instead of n+4, there can be a Transport Block (TB) size restriction,there can be a Timing Advance (TA) restriction that can limit theconfiguration of the smaller latency to small(er) cells, there can be adedicated PDSCH resource like in Semi Persistent Scheduling (SPS), wherethe ACK/NACK feedback can be similar to Rel-8, such as a dynamicACK/NACK based on a Control Channel Element (CCE) index, and where therecan be a small maximum Code Block (CB) size, such as 1500 bits insteadof 6144 bits, which can improve pipelining and/or reduce complexity. Amaximum Code Block (CB) size can correspond to the largest informationpayload size that can be channel encoded for transmission on aparticular physical channel, such as PDSCH before the informationpayload is segmented in to multiple code blocks. A transport block caninclude one or more code blocks.

For example, a device may be configured via higher layers with alow-latency transmission mode or a low-latency feature. In such a case,the device may be required to transmit the HARQ feedback faster than aRel-8 device, such as for a Downlink (DL) grant for PDSCH received insubframe n, the device may be required to transmit the correspondingHARQ-ACK feedback in subframe n+2 instead of subframe n+4. This canimply that the device processing time for a PDSCH can be reduced from3-TA to 1-TA. To ensure that the device complexity is not adverselyimpacted by this shortened processing time, there may be restrictionsimposed on TB size, and/or the TA value supported at the device forlow-latency operation. For very short transport blocks, a dedicatedPDCCH resource, like in Semi-Persistent Scheduling (SPS), can bedirectly assigned to PDSCH. This can allow the device to start detectingand decoding the PDSCH early and to send the uplink feedback muchfaster.

According to a related implementation, the device can be configured witha low latency DCI format that can work with any transmission mode. Up tothree or more Orthogonal Frequency Multiplexed (OFDM) symbols can beused for a control region. Data can be sent on Control Channel Elements(CCE's) for small packets of data. An ACK can be sent in subframe n+2 isresponse to data on a Physical Downlink Control Channel (PDCCH). In thisimplementation, a device may be configured via higher layers with alow-latency transmission mode or a low-latency feature. For smallpackets, the PDSCH that typically occupies the entire lms TTI caninstead be sent on CCE's comprising the PDCCH or control region. Sincethe control region can occur in the first 1-3 OFDM symbols of a lms TTI,the data sent on the CCE's can be decoded much earlier, such as after adevice receives 3 OFDM symbols rather than after device receives all 14OFDM symbols of a lms TTI. Due to this early decoding benefit, thedevice can then transmit the uplink feedback earlier, such as insubframe n+2, or in slot 2 of subframe n+1. The typical payloads thatcan be sent can be around 100 bits or so, and they can take advantage ofthe control channel decoder implemented in devices. The PDSCH data canbe distinguished from the DCI based on Cyclic Redundancy Check (CRC)masking with a different CRCs. This can allow for reduced complexity, nochange to existing PDSCH structure, such as TTI duration, RS, mapping,etc., only HARQ timing may be modified, and small low-latency packetscan be transmitted through a PDCCH structure.

FIG. 3 is an example illustration of a subframe 300 according to arelated possible embodiment. The subframe 300 can include OFDM symbols310 configured for low latency transmissions, resource blocks 320configured for low latency transmissions, a first set of resourceelements 330, such as first Low latency Channel Elements (LCEO), whichcan also be known as Data Channel Elements (DCE's), and a second set ofresource elements 340, such as a second LCE1. The resource blocksconfigured for low latency transmissions may be localized physicalresource blocks, localized virtual resource blocks, or distributedvirtual resource blocks. Localized Virtual Resource Blocks (VRB) can bemapped directly to physical resource blocks, while distributed virtualresource blocks may be mapped to physical resource blocks in apredetermined manner such that contiguous distributed resource blocksare mapped to non-contiguous physical resource blocks with the locationof the non-contiguous physical resource block in each slot beingdifferent. The resource blocks configured for low latency transmissionsmay be defined in terms of Resource Block Groups (RBGs), localized VRBsfrom one or more RBG subsets, or distributed VRBs. A RBG may be a set ofconsecutive virtual resource blocks (VRBs) of localized type. TheResource block group size (P) may be a function of the system bandwidth.A RBG subset p where 0≤p<P , can include every P th RBG starting fromRBG p . A LCE typically can include multiple REs and the REscorresponding to the LCE need not be contiguous in time or frequencydomain. A LCE can also be spread out between multiple RBs and evenspread out between multiple Resource Block Groups (RBGs) includingmultiple RBs. In one embodiment, a LCE may comprise REs in a RBG in oneor more OFDM symbols configured for low latency data packettransmission. In another embodiment, a LCE may comprise REs in a subsetof localized VRBs from one or more of the P RBG subsets in one or moreOFDM symbols. The subset of localized VRBs may correspond to VRBs indifferent RBGs. In another embodiment, a LCE may comprise REs in asubset of distributed VRBs in one or more OFDM symbols. The subset ofdistributed VRBs may be contiguous VRBs which as a result map tophysical RBs that are distributed. A single symbol configured for lowlatency packet transmission can include multiple LCE's in different RB'sconfigured for low latency packet transmission in the symbol. Lowlatency data packets can be on any of the symbols configured for lowlatency packet transmission, such as a subset of the symbols and canalso be on a subset of RB's configured for low latency packettransmission. In some cases all the OFDM symbols and RBs in a subframemay be potentially used for low latency transmission and separateconfiguration signalling may not be necessary. In such cases, OFDMsymbols 310 can be all the OFDM symbols in the subframe Similarly, RBs320 can be all the RBs in the subframe. Some of the OFDM symbols 350 caninclude common reference signals, like pilot RE's, on some of the RE'sin the symbols 350.

In one embodiment, similar to the control channel structure describedabove in terms of search space and aggregation levels, a UE, such as adevice, may be configured via higher layer signalling to monitor for lowlatency (LL) data packets with one or more Low latency Data Information(LDI) format(s) in a subset of the LCEs at a particular LCE aggregationlevel, L, (e.g., L=1, 2, 4 or 8 LCEs). The set of aggregated LCEs fromthe subset of the LCEs at a particular LCE aggregation level, L, cancorrespond to the set of low latency data candidates at the aggregationlevel L that the particular device monitors in a search spacecorresponding to subset of the LCEs at the particular LCE aggregationlevel, L. The device can monitor a set of low latency data candidates ata given aggregation level for low latency data packet where monitoringimplies attempting to decode each of the low latency data candidates inthe set according to all the monitored LDI formats. The device candetermine successful decoding of data payload of a low latency datapacket corresponding to a low latency data candidate by using anidentifier associated with the UE such as C-RNTI or LL-RNTI which masksor scrambles the Cyclic Redundancy Check (CRC) of the data payload. Insome embodiments, a hashing function may be used to find the low latencydata candidate locations in each search space. The hashing function maybe based on the UE RNTI (identifier associated with the UE, such asC-RNTI or LL-RNTI), aggregation level (L), the total number of LCEsavailable (Nlce), the OFDM symbol number or index, and the maximumnumber of low latency data candidates for the search space. In onemethod of determining the LCE locations S_(k) ^((L)) corresponding to alow latency data candidate m of each aggregation level L (e.g., L=(1, 2,4, or 8)), the search space for OFDM symbol ‘k’ of a subframe is givenby equation:

S _(k) ^((L)) =L{(Y _(k) +m)mod(└N _(LCE,k) /L┘)}+i   (2)

where

Y_(k)=39827·Y_(k−1) mod 65537 where Y⁻¹=n_RNTI for the UE specificsearch space;

-   -   n_RNTI≠0 is for example, C-RNTI or temporary C-RNTI or LL-RNTI;        N_(LCE,k) is the number of total LCEs available for OFDM symbol        k;    -   m=0, . . . , M^((L)))−1 where M^((L)) is the number of low        latency data candidates to monitor in the search space at        aggregation level L; and    -   i=0, . . . ,L−1 where i spans each consecutive LCE of the low        latency data hypothesis.

FIG. 4 is an example illustration of an OFDM symbol 400 according to arelated possible embodiment. The OFDM symbol can be one of the OFDMsymbols configured for low latency transmission in a subframe. The OFDMsymbol 400 can include LCE's LCE0, LCE1, and LCE2, as well as otherelements. Also, the OFDM symbol 400 can have a bandwidth of RB'sconfigured for low latency transmission, such as 12 RBs, 100 RBs, andother numbers of RB's. The LCE resources can optionally be used formarker transmission that can act as a type of control signal. Forexample, a marker transmission can be an indicator channel thatindicates whether the OFDM symbol is used for low latency traffic. Themarker can also provide information indicating the REs or sets of REs(e.g. RBGs, RBs or LCEs). The marker transmission can be sent as abroadcast transmission common to multiple devices. For a device notreceiving low latency transmission in that subframe, but having anallocation for other data transmission, the marker transmission can tellwhich RE's in its allocation are used for low latency transmissions sothat the device can ignore then, null them, or otherwise not use them.

FIG. 5 is an example illustration of a Transmit Time Interval (TTI) 500according to a related possible embodiment. The TTI 500 shows mixinglegacy with low latency allocations in one legacy TTI. For example, anew TTI can be 2-symbols long in duration. The legacy TTI 500 caninclude low latency control information C and low latency data D. Forexample, Cl can be control information for a first device and D1 can bedata for the first device, etc. The illustrated areas, such as Cl, D1,may also just have data without control information. The low latencydata and control information can coexist with legacy allocations, suchas in a 1 ms legacy TTI. The legacy allocation can be punctured 510 toaccommodate a short TTI.

According to one of these possible embodiments, a device such as device110 can receive a higher layer configuration message indicating a set ofResource Blocks (RB's) for receiving data packets in at least one symbolof a subframe. The higher layer can be higher than the physical layer.The device can attempt to decode a data packet in a first set of RE's,such as those corresponding to a first Low Latency Channel Element(LCE0), within the set of RB's. The first set of RE's can be in the atleast one symbol of the subframe. The device can attempt to decode thedata packet in at least a second set of RE's, such as thosecorresponding to a second LCE1, within the set of RB's. The second setof RE's can be in the at least one symbol of the subframe, where thesecond set of RE's can include at least one RE that is not in the firstset of RE's. The device can successfully decode the data packet in oneof the first set of RE's and the second set of RE's. The device candeliver a data payload of the decoded data packet to an applicationlayer.

For example, according to a possible implementation, a device can beconfigured with Low Latency transmission mode in a PDSCH, such as a dataregion of a regular LTE subframe. The device can look in a search spacein PDSCH region for small packets in a subframe n and can provide an ACKin a subsequent subframe n+m. As a further example, a device can beconfigured via higher layers with a low-latency transmission mode or alow-latency feature. For small packets, the PDSCH can be sent on DataChannel Elements (DCE's), such as LCE's, in the PDSCH region. For asmall packet transmission, there may be no need for sending anadditional control channel associated with it. For example, for sendinga packet of 100 bits, a DCI format of length 40-50 bits can imply anoverhead of 50%. Small packets can be decoded faster by a decoder as thepayloads can be smaller. Due to this early decoding benefit, a devicecan then transmit the uplink feedback earlier, such as in subframe n+2.The typical payloads that can be sent can be around 100 bits or so, andcan take advantage of the control channel decoder implemented indevices, such as with CRC masking with different CRC's and using searchspace similar to that defined for control channels and as describedabove. This can provide reduced complexity with minimal or no change toexisting PDSCH structure, such as TTI duration, Reference Signals (RS),mapping, etc., only HARQ timing may be modified, small low-latencypackets can be transmitted through PDSCH small RB allocations, and adevice can blind decode multiple PDSCH candidates to detect PDSCH.

According to one embodiment, a device, such as a base station device120, can transmit a resource assignment that can assign a first set oftime-frequency resources in a subframe for regular latency datatransmission. For example, the first set of time-frequency resources canbe a set of RBs in the subframe. The resource assignment can betransmitted using DCI of a control channel such as PDCCH or EPDCCH. Thedevice can transmit low latency data within a second set oftime-frequency resources in the subframe. For example, the second set oftime-frequency resources can be a set of REs mapped to one or more OFDMsymbols and one or more RBs in the subframe. Low latency data can have alower latency than regular latency data. The second set can at leastpartially overlap with the first set. The device can transmit a markersignal, where the marker signal can indicate a presence of low latencydata transmission in the subframe.

According to another related embodiment, a device, such as the device110, such as a user equipment, can receive a resource assignment. Thedevice can determine a first set of time-frequency resources in asubframe from the resource assignment. For example, the first set oftime-frequency resources can be a set of RBs in the subframe. Theresource assignment can be transmitted using DCI of a control channelsuch as PDCCH or EPDCCH. The device can determine a second set oftime-frequency resources in the subframe. For example, the second set oftime-frequency resources can be a set of REs mapped to one or more OFDMsymbols and one or more RBs in the subframe. The second set oftime-frequency resources can be used for a low latency data transmissionand can overlap with at least a portion of the first set oftime-frequency resources. The device can receive a regular latency datatransmission in the subframe. The device can decode the regular latencydata transmission in the subframe based on the determined first andsecond set of time-frequency resources, where the regular latencytransmission can have a longer latency than the low latencytransmission. The device can determine the second set of time-frequencyresources by receiving a marker signal. Alternately, the device candetermine the second set of time-frequency resources by decoding the lowlatency transmissions.

According to a possible implementation, in order to support regularlatency transmissions in the same subframe as low latency transmissions,a marker can be transmitted where the marker can indicate which RE's areused in the subframe for low latency transmission. This information canbe used to determine which Log Likelihood Ratios (LLR's) should bezeroed out while decoding regular latency transmissions. Regular latencyand low latency transmissions may be received by different users, suchas devices and/or UEs, in the same subframe. Alternately, regularlatency and low latency transmissions may be received by the same userin the same subframe, if the user is configured to receive both types oftransmissions. Alternately, some users may be configured to receiveregular latency transmissions in a first set of subframes and configuredto receive low latency transmissions in a second set of subframes. Thefirst set of subframes can be a subset of the second set of subframes.Regular latency transmissions can be transmitted in one or more RBs inthe subframe. The RBs used for regular latency transmissions can beassigned via resource assignments and indicated using control channels.Since the same subframe can be used for both regular and low latency(LL) transmissions, the REs used for LL transmission and any markertransmissions may not be used for regular latency transmissions. The REsused for LL transmission and any marker transmissions can belong to theRBs assigned for regular latency transmissions.

The marker can be sent in predefined or preconfigured locations in thesubframe. The possible locations of marker transmission can be indicatedto the user equipment via higher layer (e.g. RRC) signalling. If someOFDM symbols in the subframe are configured for low latencytransmissions, in some implementations, the marker signal can be sentonly on those OFDM symbols. For example, the marker signal can be sentin OFDM symbols 310. A user equipment attempting receive transmissionsother than low latency transmissions in the same subframe can decode themarker to determine the REs used for low latency transmissions. Forexample, the user equipment can determine the OFDM symbols 310configured for low latency transmission. Within each such OFDM symbol,for example OFDM symbol 400, the low latency transmissions can be madein some REs. The REs can be further organized as LCEs or DCEs or CCEs.For example, as shown in the OFDM symbol 400, low latency transmissionscan be made on resources or REs corresponding to LCE0, LCE1, LCE2. Whilethe OFDM symbol 400 shows LCEs created from REs in one symbol, it isalso possible to create LCEs by using REs from multiple adjacent OFDMsymbols or multiple non-adjacent OFDM symbols. In some implementations,a subset of LCEs in each OFDM symbol configured for LL transmission, forexample LCE0 in OFDM symbol 400, can be used for marker transmission.Generally, the base station may only use a portion of REs in the OFDMsymbols and RBs configured for low latency transmission in a subframe.The base station can use the marker transmission to signal informationindicating the REs used for LL transmission in each particular subframe.For example, the marker transmission can indicate which LCEs in a OFDMsymbol are used for LL transmission. Alternately, the markertransmission can indicate which RBs or RBGs of an OFDM symbol are usedfor LL transmission. A marker transmission in one OFDM symbol mayindicate the REs/LCEs/DCEs/CCEs/RBs/RBGs used for low latencytransmission in other OFDM symbols of the subframe.

FIG. 21 is an example illustration 2100 of a first subframe 2111 and asecond subframe 2112 according to a possible embodiment. The firstsubframe 2111 can include a control region 2121, low latency data 2240,and a regular latency data region 2250. The second subframe 2112 caninclude a control region 2122 including a marker 2130. A markertransmission 2130 in one subframe 2112 (e.g. subframe n+1) may indicatethe REs/LCEs/DCEs/CCEs/RBs/RBGs used for low latency transmission inOFDM symbols of another subframe 2121 (e.g. subframe n). In such cases,the marker transmission 2130 in subframe n+1 2112 can be sent in thefirst few OFDM symbols (e.g. symbols in the control region 2122), toreduce decoding latency of the device receiving the marker 2130. Whenthe marker 2130 is sent using symbols in the control region 2122,information conveyed using the marker 2130 can be sent using controlchannels, such as PDCCH or PHICH, that are typically used in the controlregion. If PDCCH is used for marker transmission, the markertransmission can be differentiated from other control channeltransmissions by using a special CRC mask (e.g. marker-RNTI) for themarker transmissions. If PHICH is used for marker transmission, one ormore of the PHICH groups can be preconfigured or predefined to be usedfor marker transmissions.

Considering implementation complexity, and decoding delay, of devices(e.g. user equipment) receiving the marker transmissions, it can beuseful to transmit the marker in every OFDM symbol configured for LLtransmission in a subframe. However, since the device (e.g. base stationor eNB) transmitting the marker may not actually transmit LLtransmissions in all the configured OFDM symbols configured for LLtransmission, it may be useful (from an overhead reduction perspective),to transmit the marker only those OFDM symbols that are actually usedfor LL transmission in the subframe. In such cases, transmission of amarker signal can implicitly indicate the presence of LL transmissions,while absence of transmission of a marker signal can implicitly indicatethe absence of LL transmissions. In other cases, where the marker istransmitted in every OFDM symbol configured for LL transmission, thepresence or absence of LL transmissions can be explicitly indicated(e.g. by using one bit or one code point) by the marker transmission.

FIG. 20 is an example illustration of a subframe 2000 according toanother possible implementation. The subframe 2000 can include a controlregion 2010, a data region 2020, a marker 2030, low latency dataresource elements 2040, and a regular latency data region 2050.According to this implementation, the marker transmission 2030 can besent by puncturing the RBs assigned for regular latency transmission2050. For example, a set of PDSCH RBs can be assigned to a user in asubframe. Some REs within an OFDM symbol (e.g. the last OFDM symbol) ofone or more of those RBs can be used for marker transmission. Ifmultiple users are assigned PDSCH RBs in the same subframe, then aseparate marker transmission for each user can be sent within theassigned RBs of each user. The marker transmission can be sent bypuncturing the user's PDSCH allocation. The puncturing can be similar toa LTE mechanism where ACK/NACK and Rank Indicator (RI) bits aretransmitted by puncturing the PUSCH allocation. The marker may betransmitted using a predefined mapping within the user's assigned RBs,such as on the last symbol and on the higher end of the RB indices ofthe user allocation.

The information payload of marker transmission, such as 13 bits or 6bits, can be used for identifying symbols, and other bits foridentifying Resource Block Groups (RBG's) punctured within the user's,such as the device's, allocation. This can be optimized by groupingallocated RBG's and identifying only the top, middle, or other groupingswithin the user's allocation as being punctured.

The information payload of marker transmission can indicate which OFDMsymbols within the user's assigned RBs are used for LL transmission. Forexample, this can be done using 13 bits or 6 bits with each bitcorresponding to one or more OFDM symbols. The payload bits of themarker transmission may be used to identify Resource Block Groups(RBG's) that contain LL transmission within the RBs assigned for theuser for receiving regular latency transmission. The payload can befurther optimized by grouping the assigned RBs into RBG's andidentifying only the top, middle, or other groupings that contain LLtransmissions.

The marker transmission may only be sent if LL transmissions overlapresource allocations of users scheduled with a particular set ofmodulation of Modulation and Coding Scheme (MCS) levels. For example, ifthe LL transmissions overlap only those resource allocations with lowMCS levels (e.g. those corresponding to QPSK modulation and low codingrate, such as <0.8), the marker signal may not be transmitted. If the LLtransmissions overlap resource allocations with high MCS levels (e.g.those corresponding to 64 QAM or higher modulation), the marker signalcan be transmitted. In another example, no marker may be used for lowMCS, such as MCS<10.

According to a possible implementation, a device (e.g. user equipment110) can receive a subframe with both regular latency and low latencytransmissions. The device may be configured to receive both regular andlow latency (LL) transmissions in the same subframe. Alternatively,while the subframe can contain both regular latency and low latencytransmissions, the device may be configured to decode only regularlatency transmissions. However, even if the device is decoding onlyregular latency transmissions, it can be useful for the device to takeinto account the presence of LL data transmissions in the subframe tomore accurately decode the regular latency data transmissions.Accordingly, the device can receive a resource assignment. The devicecan determine a first set of time-frequency resources from the resourceassignment. For example, the first set of time-frequency resources canthe REs corresponding to PDSCH RBs assigned to the device for receivingdata transmissions. The data transmissions can be regular latency datatransmissions. The device may receive the resource assignment on acontrol channel such as PDCCH/EPDCCH. The device can determine a secondset of time-frequency resources in the subframe. The second set of timefrequency resources can overlap with at least a portion of the first setof time-frequency resources and the second set of time frequencyresources can be used for low latency (LL) data transmissions. Forexample, the device may be assigned RB1,RB2,RB3,RB4,RB5 in both 0.5 mstime slots of a lms subframe for receiving regular latencytransmissions. Each RB can span all the OFDM symbols in a time slot. ALL transmission may span RB3, RB4, RB5, RB6, RB7, and RB8 in frequencydomain and OFDM symbols 4 and 5 of the first slot of the subframe intime domain. The device can then determine the REs within RB3, RB4, andRB5 and OFDM symbols 4 and 5 of the first slot of the subframe as thesecond set of time-frequency resources.

The device can then decode the regular latency data transmissions in thesubframe based on the first and second set of time-frequency resources.For the example given above, while decoding the data for regular latencydata transmissions, the device can adjust the log likelihood ration(LLR) values of bits corresponding to the regular latency datatransmission that were mapped to REs within RB3, RB4, and RB5 and OFDMsymbols 4 and 5 of the first slot of the subframe to a low value. Forexample, the device can set the LLR values of those bits to zero. Thiscan improve the probability that the device correctly decodes the datatransmission assigned on PDSCH RBs RB1, RB2, RB3, RB4, and RB5. Such canoperation can be useful if the MCS level used for the data transmissioncorresponds to a level with higher order modulation and higher codingrate (e.g. 64 QAM modulation or higher and code rate 0.7 or higher). Ifthe MCS level used for the data transmission corresponds to a level withlower order modulation and lower coding rate (e.g. 16 QAM modulation orlower and code rate less than 0.7), the device may skip the step ofdetermining the second set of resources and adjusting LLR values, andinstead directly attempt to decode the regular data transmissionaccording to the resource assignment.

In some implementations, the device may receive a marker signal. Thedevice can use the marker signal to determine the second set oftime-frequency resources. The device can determine the location ofmarker signal based on a pre-defined location of the marker signal. Forexample, the device may determine from RRC signalling that LLtransmissions are expected in RB3-RB8 and RB91-RB96 in the frequencydomain and OFDM symbols 4 and 5 of the first slot and OFDM symbols 0, 1,4, and 5 of the second slot in the time domain of every subframe.

FIG. 22 is an example illustration of a subframe 2200 according to apossible embodiment. The subframe 2200 can include a control region2210, a data region 2220, a marker 2230, low latency data 2240 and aregular latency data region 2250. For a subframe where the devicereceives a resource assignment, the device can then determine that amarker signal can be present in RB0-RB2 in OFDM symbols 4 and 5 of thefirst slot and OFDM symbols 0, 1, 4, and 5 of the second slot in timedomain of the subframe. In this example, the possible locations of amarker signal can be a predefined set of RBs (e.g. RB0-RB2) in everyOFDM symbol configured for LL transmission. In another example, where LLtransmissions are made using LCEs, the device can look for the markersignal in REs corresponding one or more predefined LCEs (e.g. marker istransmitted in LCE0 in OFDM symbols where LCEs with LL transmissions arepossible).

After receiving the marker signal, by decoding the information payloadin the marker signal, the device can determine the REs where LLtransmissions are present, and the device can further determine which ofthose REs overlap with the REs assigned to the device for receivingregular latency data transmission. Therefore, the device can determine asecond set of time-frequency resources in the subframe, the second setof time-frequency resources used for a low latency data transmission,and the second set of time-frequency resources overlapping with at leasta portion of the first set of time-frequency resources based on themarker signal.

In some implementations, the device may be able to receive both regularand low latency (LL) transmissions in the same subframe. For example,the device may be assigned RB1, RB2, RB3, RB4, and RB5 in both 0.5mstime slots of a lms subframe for receiving regular latencytransmissions. The REs corresponding to these RBs can be considered as afirst set of time-frequency resources. The device may successfullydecode a LL transmission that spans RB3, RB4, RB5, RB6, RB7, and RB8 inthe frequency domain and OFDM symbols 4 and 5 of the first slot of thesubframe in the time domain. The REs on which the LL transmission isdecoded can be considered as a third set of time-frequency resources.The device can then determine a second set of time-frequency resourcesas time-frequency resources belonging to both the first set oftime-frequency resources and the third set of time-frequency resources.For example, the REs within RB3, RB4, and RB5 and OFDM symbols 4 and 5of the first slot of the subframe can be considered as the second set oftime-frequency resources. The device can then decode the regular latencydata transmission by setting the LLR=0 for bits mapped to the second setof time-frequency resources.

In such implementations, a separate marker signal transmission may notbe required. Furthermore, in such implementations, the LL transmissionscan be made decodable also by devices that are configured to decoderegular latency transmissions (i.e., non-low latency devices). Forexample, all the LL transmissions can use the same CRC mask, and can beblindly decoded by both low latency device and non-low latency devices.However, the individual data payload of each low latency transmissioncan be scrambled so that even though non-low latency devices are abledecode the LL transmissions, they cannot unscramble data payload bits,thereby ensuring the privacy of LL data payload. The non-low latencydevices may attempt to decode only those LL allocations that can overlapwith their PDSCH resource allocation for regular latency datatransmission. If a LL allocation is successfully decoded, the non-lowlatency device can determine the overlapping REs with its regularlatency allocation, and erase the LLR values, such as by zeroing them ofthe bits corresponding to the overlapping REs..

According to a possible embodiment, a device can receive a higher layerconfiguration. The higher layer configuration can be higher than aphysical layer configuration. The higher layer configuration canindicate configuring the device with a low latency configuration for alow latency transmission mode in addition to a regular latencyconfiguration for a regular latency transmission mode. The low latencytransmission mode can have a shorter latency than the regular latencytransmission mode. The device can receive a packet based on one of thelow latency configuration and the regular latency transmission mode in asubframe n. The device can transmit a feedback packet in a followingsubframe n+p, where p<4 when the received packet is based on the lowlatency configuration. The following subframe n+p can be the pthsubframe from the subframe n. The device can transmit a feedback packetin a following subframe n+4 when the received packet is based on theregular latency configuration. The following subframe n+4 can be thefourth subframe from the subframe n.

According to a possible implementation, in LTE, Code Block (CB)segmentation can be used to segment a large transport block in tosmaller pieces and these small pieces are individually CRC-encoded,turbo coded, rate-matched, scrambled, and mapped to modulation symbols.For increased pipelining benefit, a single modulation symbol or RE maynot contain bits from different code blocks. The code blocks for a givenTransport Block (TB) can be mapped in a frequency-first mapping as shownin the TB 600. The TB 600 can assume a transport block segmented intofour code blocks occupying the subframe. Assuming two Common ReferenceSignal (CRS) ports, a 50 RB system bandwidth, of the OFDM symbols 0-13in a 1 millisecond TTI, symbol #{0,5,7,12} can have RE's for CRS. Thus,OFDM symbols other than {0,5,8,12} can have 12*50=600 RE's for data,while {0,5,7,12} can have 8*50=400 RE's. Typically, based onsignals/channels (CRS, CSI-RS, CSI-IM, DRS, DMRS, PBCH, etc.), thenumber of RE's per any given OFDM symbol, or per any given resourceblock can be variable.

For channel estimation latency, if a device is required to demodulatePDSCH based on CRS, then for lms TTI, the CRS channel estimation may notstart until symbol 5 (˜6*71 us=420 us), contributing a latency of 0.42ms. This can imply, for code block 0 in the TB 600, the Log-LikelihoodRadios (LLR's) cannot be generated until symbol 5, such as after CB0 isfully received. I.e., the RE's corresponding to CBO are fully receivedby symbol 3, and the I/Q values for symbols 0-4 are waiting for symbolduration 4 and 5, after receiving symbol 5, and CRS channel estimationcan be performed and then LLR's for CB0 can be generated to kick-start aturbo decoding process. It is possible to start early decoding byrelying only on CRS in symbol 0. Typically, all the CRS RE's in a givensubframe can be used for PDSCH demodulation. Also, cross-subframechannel estimation for CRS is not assumed here. For DMRS based channelestimation, a device may have to wait until at least symbol 7 forperforming DMRS based channel estimation. Typically, DMRS from bothslots can be used for improving channel estimation. To make possibleimprovements, more demodulation pilots can be introduced to aid earlydecoding and pilot for channel estimation may be received no later thancorresponding data. Also, a demodulation pilot can be introduced inearly locations. For example, DMRS can be transmitted in symbol 0,1 andsymbol 7,8. This can cut DMRS channel estimation latency by almost 420us. Additionally, Channel State Information Reference Signal (CSI-RS)and Channel State Information Interference Measurement (CSI-IM) may berequired mainly for feedback purposes. Therefore, these referencesignals can be transmitted in a flexible location where the devicecomplexity can be dependent on the time between when CSI is measured andwhen it is to be reported.

FIG. 7 is an example illustration of a transport block 700 according toa possible embodiment. FIG. 8 is an example illustration of a transportblock 800 according to a possible embodiment. The transport blocks 700and 800 can have 13 code blocks and can occupy a 1 ms subframe, wherethe vertical dimension is frequency and the horizontal dimension istime. The transport block 700 can include code blocks CB0-CB12 occupyinginteger number of OFDM symbols. The transport block 800 can include codeblocks CB0-CB12, where each code block can occupy one or more OFDMsymbols. LTE can use code block-based transmitter and receiver operationfor pipelined decoder implementation. If a Transport Block (TB)exceeding a size of 6120 bits (6144 with TB CRC) is to be transmitted,the transport block can get segmented into multiple code blocks, whereeach code block can have a CRC attached, can be turbo coded, can berate-matched, and can be mapped to modulation symbols. This can allowfor pipelined implementation, as each code block can be processedindependently and sequentially, which can reduce complexity. HARQfeedback and retransmissions can typically be performed at a transportblock level.

In LTE, a Transport Block Size (TBS) of 75376 bits corresponding to ⅚,64 QAM, 100 RB allocation can be segmented into 13 code blocks, each ofsize 5824 bits (=(75376+(13+1)*24)/13, with 14 24-bit CRC's). Thetransport block 700 illustrates CB mapping to the 1 ms TTI. The mappingcan be based on the total number of available RE's in the assignedresource blocks, such as in all assigned OFDM symbols. The availablenumber of RE's can be affected by the amount of signals/channels, suchas CRS, CSI-RS, CSI-IM, DRS, PSS/SSS, etc., present in the assignedresource blocks. Thus, a transport block can look like the transportblock 800, where each code block may span one or more OFDM symbols.

A device configured with Low-Latency transmission mode, such as lowlatency DCI format, can transmit HARQ ACK in n+2 instead of n+4, canhave a TB size restriction, can have a TA restriction that can limit theconfiguration of the smaller latency to small(er) cells, and can havededicated PDSCH resource like in SPS. The ACK/NACK feedback can besimilar to Rel-8, such as dynamic ACK/NACK based on control channel CCEindex or as in SPS. The device can be configured via higher layers witha low-latency transmission mode or a low-latency feature. In such acase, the device may be required to transmit the HARQ feedback fasterthan a Rel-8 device. For example, for a downlink grant for PDSCHreceived in subframe n, the device may be required to transmit thecorresponding HARQ-ACK feedback in subframe n+2 instead of subframe n+4.This can imply that the device processing time for a PDSCH can bereduced from 3-TA to 1-TA. To ensure that the device complexity is notadversely impacted by this shortened processing time, there may berestrictions imposed on the transport block size, and/or the timingadvance value supported at the device for low-latency operation. Forvery short transport blocks, dedicated PDCCH resource like inSemi-Persistent Scheduling (SPS) can be directly assigned to the PDSCH.This can allow the device to start detecting and decoding the PDSCHearly and to send the uplink feedback much faster. This can provide forreduced complexity complex with no or minimal change to the existingPDSCH structure, such as to TTI duration, RS, mapping, etc., can providefor only modifying HARQ timing, and can provide for some decoderrelaxation via TA/TB restriction. In order to support low latencyoperation, the device can be configured with a transmission mode thatuses restricted transport block sizes, restricted timing alignment,dedicated PDSCH resources like in SPS, and smaller maximum CB size, suchas 1500 bits instead of 6144 used in LTE rel-13. To minimize collisionsin the uplink, the device can be configured with an extended UL ACK/NACKregion either on a slot level or symbol level based on the length of theTTI being used.

FIG. 9 is an example illustration of a legacy or regular 1 ms uplinksubframe 900 according to a possible embodiment. The subframe 900 caninclude two slots 910 and 920. FIG. 10 is an example illustration of a 1ms uplink subframe 1000 and at least one 0.2 ms uplink subframe 1010overlaid on the lms subframe 1000 according to a possible embodiment.FIG. 11 is an example illustration of a 1 ms subframe 1100 according toa possible embodiment. The subframe 1100 shows another potential framestructure for an uplink wherein the subframe 1100 can include twosymbols 1110 and 1120 with resource elements 1130 and 1140 assigned to adevice for uplink feedback transmission in a multi-carrier clusterformat. One symbol 1130 can be used for a pilot and one symbol 1140 canbe used for an ACK/NACK.

FIG. 12 is an example flowchart 1200 illustrating the operation of awireless communication device, such as the first device, according to apossible embodiment. At 1210, the flowchart 1200 can begin. At 1220, ahigher layer configuration message can be received. The higher layer canbe higher than a physical layer.

At 1230, a first region of a subframe for receiving data packets can bedetermined based on the higher layer configuration message. The firstregion can be a first time-frequency region in a sequence of regions.For example, the first region can be a first chronological region of asubframe, where the first region can include up to four multicarriersymbols. For example, a multicarrier symbol can be an OFDM symbol and asubframe can include up to 14 OFDM symbols. Also, a subframe can be oneof ten subframes in a frame. The first region can include a first set ofresource elements. The resource elements in the first set of resourceelements can be used for low latency data packets, can be used forcontrol signals, and/or can be used for other purposes. The first set ofresource elements can be a subset of a second set of resource elementsin the first region. The number of resource elements in the first setcan be less than the number of resource elements in the second set. Thefirst region can be used for control channel monitoring. For example,the first region can be a control region including at least one physicaldownlink control channel that includes control channel elements. Thedata packets can be transmitted on one or more of the control channelelements including resource elements from the first set of resourceelements. Also, the data packets can be mapped to at least one resourceelement of the first set of resource elements.

The data packets in the first region can be low latency data packetsthat have a lower maximum allowed latency than normal latency datapackets in a second region. The first region can be used fortransmitting control signals for decoding the normal latency datapackets in the second region. For example, normal latency data packetscan be legacy data packets.

At 1240, the first region can be monitored. For example, control channelmonitoring can be performed in the first region. Monitoring can includeattempting to decode the data packets in the first region. For example,monitoring can imply, such as include, blind decoding data packets.

At 1250, data in the data packet in the first region can be decoded. Thedata packet can be a low latency data packet with a latency lower than anormal data packet. Also, successful decoding of a control channel inthe first region can be determined using a first identifier. The firstidentifier can be a Cell Radio Network Temporary Identifier (C-RNTI)received in the higher layer configuration message. Successful decodingof data in the data packet in the first region can also be determinedusing a second identifier. The second identifier can be a Low LatencyRadio Network Temporary Identifier (low latency-RNTI) received in thehigher layer configuration message.

At 1260, an acknowledgement can be transmitted in a subframe with afirst offset from a subframe in which the low latency data packet isreceived in response to successful decoding of low latency data packet.The first offset can be different from a second offset used for normallatency data packets. For example, the first offset can be two andtransmitting an acknowledgement can include transmitting a hybridautomatic repeat request acknowledgement in a subframe with a firstoffset of two subframes n+2 from the subframe n in which low latencydata packet is received. At 1270, the decoded data from the data packetin the first region can be delivered to an application layer. At 1270,the flowchart 1200 can end.

A variation on the above embodiment can include receiving a higher layerconfiguration message, the higher layer being higher than a physicallayer. The higher layer configuration message can be received before thesubframe discussed below. A first region of a subframe for receiving lowlatency data packets can be determined based on the higher layerconfiguration message. The first region can be a control region of acertain number of first symbols in a subframe. For example, the firstregion can be a control region including a physical downlink controlchannel including control channel elements. Low latency data packets canbe transmitted on one or more control channel elements. Low latency canrefer to how quickly data can be received correctly. For example, it canrefer to the amount of time from a time a packet arrives at a basestation to the time the packet is received at a UE. The latency can alsorefer to the round trip latency, such as from when a base station sendsa packet to the time the base station receives a user equipmentacknowledgement receipt of the packet.

The first region can be used for control channels that assign resourceallocation for normal latency data packets in a second region after thefirst region in the subframe. Low latency data packets can have a lowermaximum allowed latency than normal latency data packets. The firstregion can also be used for the low latency data packets.

Low latency data packets can be monitored in the first region inresponse to receiving the higher layer configuration. Monitoring caninclude attempting to decode a low latency data packet in the firstregion. For example, monitoring can imply blind decoding data packets.Attempting to decode data packets can include blind decoding datapackets.

Data in the low latency data packet in the first region can besuccessfully decoded. An acknowledgement can be transmitted in asubframe with a first offset from a subframe in which the low latencydata packet is received in response to successful decoding of lowlatency data packet, where the first offset can be different from asecond offset used for normal latency data packets. For example, thefirst offset can be two and transmitting an acknowledgement can includetransmitting a hybrid automatic repeat request acknowledgement in asubframe with a first offset of two subframes n+2 from the subframe n inwhich low latency data packet is received. The decoded data from thesuccessfully decoded low latency data packet in the first region can bedelivered to higher layers than a physical layer.

A transport block can be used that can include the number of informationbits decoded from data resource elements in resource blocks allocated toa device excluding reference signals in the allocated resource blocks.Similarly the transport block can be the number of information bitsencoded by a base station and sent on data resource elements in resourceblocks allocated to a device. Packets can be mapped to transport blocks.A transport block can be segmented into more than one code blocks if thetransport block size exceeds the maximum code block size. Packets can beused in higher layers and resource elements in resource blockscorresponding to the packet can be sent on the physical layer. Atransmission time interval can indicate a time duration of a dataallocation. For example, a transmission time interval can include one ormore subframes.

FIG. 13 is an example flowchart 1300 illustrating the operation of awireless communication device, such as the device 110, according to apossible embodiment. The flowchart 1300 can provide for looking for adata packet in different locations. Low latency data packets can be onany of the symbols configured for low latency packet transmission, suchas on a subset of the symbols. The low latency data packets can also beon a subset of resource blocks configured for low latency packettransmission.

At 1310, the flowchart 1300 can begin. At 1320, a higher layerconfiguration message can be received. The higher layer configurationmessage can indicate a set of resource blocks for receiving data packetsin at least one symbol of a subframe. The at least one symbol can beoutside of a control region of a subframe. The higher layerconfiguration message can also indicate a set of candidate symbols inthe subframe, the at least one symbol belonging to the set of candidatesymbols, the set of candidate symbols being less than all of the symbolsin the subframe. The higher layer configuration message can furtherindicate a location of the at least one symbol of the subframe.

At 1330, an attempt can be made to decode a data packet in a first setof resource elements within the set of resource blocks. Attempting todecode can mean monitoring and/or blind decoding. The first set ofresource elements can be in the at least one symbol of the subframe. Thefirst set of resource elements are not necessarily the first absoluteresource elements in the set of resource blocks. The first set ofresource elements can be a first Low latency Channel Element (LCE0)including the first set of resource elements within the set of resourceblocks. A LCE can include resource elements in orthogonal frequencymultiplexed symbols configured for low latency transmission in aresource block configured for low latency transmission. A LCE can alsobe spread out between multiple resource blocks and even spread outbetween multiple Resource Block Groups (RBG's) including multiplecontiguous resource blocks. Also, a single symbol configured for lowlatency packet transmission can include multiple LCE's in differentresource blocks configured for low latency packet transmission in asymbol. The first set of resource elements can further be a subset ofresource elements used for control channel monitoring in a subframe,where the control channel can assign resources in a second region of thesubframe for data. For example, the first set of resource elements canbe in a control region of the subframe.

At 1340, an attempt can be made to decode the data packet in at least asecond set of resource elements within the set of resource blocks. Thefirst set of resource elements and second set of resource elements eachcan be in channel elements that include multiple resource elements thatare not necessarily contiguous with each other in time and/or frequency.The second set of resource elements can be in the at least one symbol ofthe subframe. The second set of resource elements can include at leastone resource element that is not in the first set of resource elements.The second set of resource elements can be a second Low latency ChannelElement (LCE1) including at least the second set of resource elements awithin the set of resource blocks.

A first number of resource elements in the first set of resourceelements can be based on a first aggregation level. A second number ofresource elements in the second set of resource elements can be based ona second aggregation level higher than the first aggregation level. Thesecond set of resource elements can include the first set of resourceelements and additional resource elements. The first set of resourceelements may also be different resource elements than resource elementsin the second set of resource elements. A number of the additionalresource elements can be the same as the first number of resourceelements in the first set of resource elements. For example, theaggregation level can be doubled, such as aggregation level 2. Thenumber of additional resource elements can also be greater than thefirst number of resource elements, such as aggregation levels of 4 and8.

At 1350, the data packet in one of the first set of resource elementsand the second set of resource elements can be successfully decoded. At1360, an ACK can be transmitted in response to successfully decoding thefirst packet. The subframe can be a first subframe and the ACK can betransmitted in a time-frequency resource in a second subframe with afirst offset to the first subframe. For example, the second subframe canbe n+2 from the first subframe n. According to a possible embodiment,the higher layer configuration message can indicate a set of resourceblocks for receiving low latency data packets in at least one symbol ofa subframe, the higher layer being higher than a physical layer. Thedata packet can be a low latency data packet. An attempt can be made todecode control information in the subframe, such as in a control regionof the subframe. The control information can assign resources forreceiving a normal latency data packet, where the normal latency datapacket can have a longer latency that the low latency data packet. Inresponse to decoding the normal latency data packet, an ACK/NACK can betransmitted in a third subframe with a second offset to the firstsubframe, where the second offset is greater than the first offset. At1370, a data payload of the decoded data packet can be delivered to anapplication layer. At 1380, the flowchart 1300 can end.

FIG. 14 is an example flowchart 1400 illustrating the operation of awireless communication device, such as the device 110, according to apossible embodiment. At 1410, the flowchart 1400 can begin. At 1420, ahigher layer configuration can be received at the device. The higherlayer configuration can be higher than a physical layer configuration.The higher layer configuration can indicate configuring the device witha low latency configuration for a low latency transmission mode inaddition to a regular latency configuration for a regular latencytransmission mode. The low latency transmission mode can have a shorterlatency than the regular latency transmission mode. A transport block ofthe low latency configuration can be smaller than a transport block forthe regular latency configuration. A code block size in a subframe forpackets based on the low latency configuration can be smaller than acode block size for packets based on the regular latency configuration.For example, the code block size can be less than a regular latency codeblock size of 6144 bits. Also, a maximum timing advance value for thelow latency configuration can be less than a maximum timing advancevalue for the regular latency configuration.

At 1430, a packet can be received based on one of the low latencyconfiguration and the regular latency transmission mode in subframe n.The packet based on the low latency configuration can be received on adedicated resource on a Physical Downlink Shared Channel (PDSCH). Forexample, for very short transport blocks, dedicated PDSCH resources,like in Semi Persistent Scheduling (SPS), can be directly assigned tothe device. This can allow the device to start detecting and decodingthe PDSCH early and to send the uplink feedback much faster because acontrol channel is not necessary, which can avoid latency from usingcontrol channel transmissions.

At 1440, a determination can be made as to whether the received packetis based on the low latency configuration or on a regular latencytransmission. For example, the packet can be identified as being basedon the low latency configuration based on the packet being received on agiven transport bearer. A transport bearer can be an IP packet flow witha defined Quality of Service (QoS) between a packet gateway and adevice. For example, there are Voice over Internet Protocol (VoIP)bearers that require a QoS with a minimum bit rate guarantee, FileTransfer Protocol (FTP) bearers that requires a best effort QoS with anon-guaranteed bit rate, web browsing bearers with a best effort QoS,and other types of bearers. Low latency packets can have a low latencybearer, such as gaming, VoIP, and other applications that require lowerlatency. The packet can also be identified as being based on the lowlatency configuration based on the packet being received from a certaincell. For example, the packet can be identified as being a low latencypacket when multiple packets are received from the certain cell. Inparticular, packets can be received from different cells, such as withcarrier aggregation, and the device can be configured to receive lowlatency packets from one or more of the different cells.

At 1450, if the packet is based on the low latency configuration, afeedback packet can be transmitted in a following subframe n+p, wherep<4. The following subframe n+p can be the p^(th) subframe from thesubframe n. For example, the feedback packet can be a hybrid automaticrepeat request acknowledgement sent in the following subframe that istwo subframes n+2 after the first subframe n in response to receivingthe receiving the packet based on the low latency configuration in thefirst subframe n. The hybrid automatic repeat request acknowledgementcan be transmitted in a temporal portion of the subframe including atleast two symbols with resource elements assigned to the device foruplink feedback transmission. One symbol of the at least two symbols canbe used for a pilot symbol and another symbol of the at least twosymbols can be used for the hybrid automatic repeat requestacknowledgement.

At 1460, if the packet is based on the normal latency configuration, afeedback packet can be transmitted in a following subframe n+4 when thereceived packet is based on the regular latency configuration. Thefollowing subframe n+4 can be the fourth subframe from the subframe n.At 1470, the flowchart 1400 can end.

FIG. 15 is an example flowchart 1500 illustrating the operation of awireless communication device, such as the device 120, according to apossible embodiment. The method can be performed in a base station, suchas an eNB, and/or can also be performed in any other device, such as aUE in a peer-to-peer network, an access point, or any other device thatcan transmit data. The flowchart 1500 describes, among other things,different features for signaling the existence and/or location of lowlatency data transmissions. Thus, all of the features are not necessary,as some may be redundant. At 1510, the flowchart 1500 can begin.

At 1520, higher layer signaling can be transmitted in a subframe. Thehigher layer can be a layer higher than a physical layer. The higherlayer signaling can indicate a set of OFDM symbols where low latencydata may be transmitted, a set of resource blocks where low latency datamay be transmitted, a set of OFDM symbols where marker signal may betransmitted, and/or a set of resource elements where marker signal maybe transmitted. The set can include just one symbol or block or can evenbe zero, such as empty.

At 1530, a resource assignment can be transmitted. The resourceassignment can assign a first set of time-frequency resources in asubframe for regular latency data transmission. The subframe can beafter the subframe in which the higher layer signaling is transmitted.

At 1540, regular latency data can be transmitted in resources within afirst set of time-frequency resources in which low latency data is nottransmitted. For example, regular latency data can be transmitted withinat least some of the first set of time-frequency resources in which lowlatency data is not transmitted.

At 1550, low latency data can be transmitted within a second set oftime-frequency resources in the subframe. The second set can at leastpartially overlap with the first set. The low latency data can have alower latency than regular latency data. The low latency data within thesecond set of time-frequency resources may or may not occupy all of theresources in the second set.

At 1560, a marker signal can be transmitted. The marker signal canindicate a presence of low latency data transmission in the subframe. Ahigher layer can indicate where the marker can be transmitted, such aswhich of different candidate marker locations is being used. The markersignal can be transmitted in a subframe immediately following thesubframe that includes the time-frequency resources. A control channelcan be transmitted as the marker signal in the immediately followingsubframe. The control channel can indicate the presence of low latencydata transmission in the subframe that includes the time-frequencyresources. The marker signal can also be transmitted in the subframewhere low latency data on the second set of time-frequency resources istransmitted.

The second set of time-frequency resources can include at least a set ofOFDM symbols in the subframe and the marker signal can be transmitted inthe at least one OFDM symbol of the set of OFDM symbols. For example,the marker signal can indicate a third set of time-frequency resourcesthat include at least the time-frequency resources within the at leastone OFDM symbol where low latency data is transmitted. The marker signalcan also indicate the time-frequency resources within the at least oneOFDM symbol where low latency data is transmitted. The marker signal canadditionally indicate at least some of the time-frequency resourceswithin the at least one OFDM symbol where low latency data istransmitted. The marker signal can be transmitted in a Low latencyChannel Element (LCE) that can include a third set of time-frequencyresources within the second set time-frequency resources. The third setof time-frequency resources can be within the at least one OFDM symbol.

The second set of time-frequency resources can be at least a set of OFDMsymbols in the subframe and the marker signal can be transmitted in allOFDM symbols of the set of OFDM symbols. The first set of time-frequencyresources can be a set of resource blocks in the subframe and the markersignal can be transmitted in at least one resource block of the set ofresource blocks. For example, the marker signal can be transmitted inthe last symbol of the in the at least one resource block of the set ofresource blocks. The marker signal can also indicate the presence orabsence of low latency data transmission in the subframe. At 1570, theflowchart 1500 can end.

FIG. 16 is an example flowchart 1600 illustrating the operation of awireless communication device, such as the device 110, according to apossible embodiment. The flowchart 1600 describes, among other things,different features for determining the existence and/or location of lowlatency data transmissions. Thus, all of the features are not necessary,as some may be redundant. At 1610, the flowchart 1600 can begin.

At 1615, higher layer signaling can be received in a subframe, where thehigher layer can be a layer higher than a physical layer. The higherlayer signaling can indicate a set of OFDM symbols where low latencydata may be transmitted, a set of resource blocks where low latency datamay be transmitted, a set of OFDM symbols where a marker signal may betransmitted, and/or a set of resource elements where a marker signal maybe transmitted. The set can be just one symbol or block and/or can bezero, such as empty.

At 1620, a resource assignment can be received. At 1625, a Modulationand Coding Scheme (MCS) value can be determined from the resourceassignment. At 1630, a first set of time-frequency resources in asubframe can be determined from the resource assignment. The subframecan be a first subframe. The first set of time-frequency resources caninclude a set of resource blocks in the subframe.

At 1635, a marker signal can be received. The marker signal can bereceived in at least one resource block of the set of resource blocks.The marker signal can additionally be received in a second subframeimmediately following the first subframe. The marker signal can also bereceived in the first subframe containing the first set oftime-frequency resources. For example, the marker signal can be receivedin the at least one OFDM symbol of the first subframe. A control channelcan be received as the marker signal in the second subframe. The controlchannel can indicate the presence of low latency data transmission inthe first subframe. The marker signal can also indicate the presence orabsence of low latency data transmission in the subframe.

At 1640, a second set of time-frequency resources in the subframe can bedetermined. The second set of time-frequency resources can be used for alow latency data transmission and can overlap with at least a portion ofthe first set of time-frequency resources. The second set oftime-frequency resources can be determined based on the received markersignal. The second set of time-frequency resources can include at leasta set of OFDM symbols in the subframe and the marker signal can bereceived in all OFDM symbols of the set of OFDM symbols. The markersignal received at 1635 can also indicate a third set of time-frequencyresources. The third set of time-frequency can include at least thetime-frequency resources within the at least one OFDM symbol where lowlatency data is received.

According to a possible implementation, a low latency data transmissioncan be successfully decoded on a third set of time-frequency resourcesin the subframe. Then, the second set of time-frequency resources can bedetermined as time-frequency resources belonging to both the first setof time-frequency resources and the third set of time-frequencyresources.

At 1645, Log Likelihood Ratio (LLR) values can be adjusted. The adjustedLLR values can be values of bits corresponding to regular latency datatransmission and mapped to the second set of time-frequency resources.Adjusting LLR values can include adjusting soft bit values. The LLRvalues can be set to zero. The LLR values may be adjusted only if theMCS value exceeds a MCS threshold. For example the MCS threshold cancorrespond to 16 QAM rate ¾. If the MCS determined from resourceassignment is smaller than the threshold, the device may not adjust theLLR values.

At 1650, a regular latency data transmission in the subframe can bedecoded based on the determined first and second set of time-frequencyresources. The regular latency transmission can have a longer latencythan the low latency transmission. The regular latency data transmissioncan be intended for the device. A low latency data transmission may ormay not be intended for the device. The regular latency transmission inthe subframe can be decoded based on the adjusted LLR. The regularlatency transmission can also be decoded based on the zeroed bitscorresponding to regular latency data transmission and mapped to thesecond set of time-frequency resources. Regular latency data can bedecoded without accounting for the second set of resources when the MCSvalue is less than a threshold. For example, regular latency data can bereceived in resources within the first set of time-frequency resourcesin which low latency data is not transmitted and then the regularlatency data can be decoded. As a further example, regular latency datain resources can be received within at least some of the first set oftime-frequency resources in which low latency data is not received. Theregular latency data can be received in at least some of the resourceswithin the first set of time-frequency resources. For example, thedevice can determine an MCS value from the resource assignment and ifthe MCS is less than a MCS threshold it may not look for a marker and/orskips the step of determining a second set of resources, and can decoderegular latency data without accounting for second set of resources. At1655, the flowchart 1600 can end.

It should be understood that, notwithstanding the particular steps asshown in the figures, a variety of additional or different steps can beperformed depending upon the embodiment, and one or more of theparticular steps can be rearranged, repeated or eliminated entirelydepending upon the embodiment. Also, some of the steps performed can berepeated on an ongoing or continuous basis simultaneously while othersteps are performed. Furthermore, different steps can be performed bydifferent elements or in a single element of the disclosed embodiments.

FIG. 17 is an example block diagram of an apparatus 1700, such as thedevice 110, according to a possible embodiment. The apparatus 1700 caninclude a housing 1710, a controller 1720 within the housing 1710, audioinput and output circuitry 1730 coupled to the controller 1720, adisplay 1740 coupled to the controller 1720, a transceiver 1750 coupledto the controller 1720, an antenna 1755 coupled to the transceiver 1750,a user interface 1760 coupled to the controller 1720, a memory 1770coupled to the controller 1720, and a network interface 1780 coupled tothe controller 1720. The elements of the apparatus 1700 can perform thedevice and apparatus methods and processes described in the disclosedembodiments.

The display 1740 can be a viewfinder, a liquid crystal display (LCD), alight emitting diode (LED) display, a plasma display, a projectiondisplay, a touch screen, or any other device that displays information.The transceiver 1750 can include a transmitter and/or a receiver. Theaudio input and output circuitry 1730 can include a microphone, aspeaker, a transducer, or any other audio input and output circuitry.The user interface 1760 can include a keypad, a keyboard, buttons, atouch pad, a joystick, a touch screen display, another additionaldisplay, or any other device useful for providing an interface between auser and an electronic device. The network interface 1780 can be auniversal serial bus port, an Ethernet port, an infraredtransmitter/receiver, a USB port, an IEEE 1394 port, a WLAN transceiver,or any other interface that can connect an apparatus to a network orcomputer and that can transmit and receive data communication signals.The memory 1770 can include a random access memory, a read only memory,an optical memory, a flash memory, a removable memory, a hard drive, acache, or any other memory that can be coupled to a wirelesscommunication device.

The apparatus 1700 and/or the controller 1720 may implement anyoperating system, such as Microsoft Windows®, UNIX®, or LINUX®,Android™, or any other operating system. Apparatus operation softwaremay be written in any programming language, such as C, C++, Java orVisual Basic, for example. Apparatus software may also run on anapplication framework, such as, for example, a Java® framework, a .NET®framework, or any other application framework. The software and/or theoperating system may be stored in the memory 1770 or elsewhere on theapparatus 1700. The apparatus 1700 and/or the controller 1720 may alsouse hardware to implement disclosed operations. For example, thecontroller 1720 may be any programmable processor. Disclosed embodimentsmay also be implemented on a general-purpose or a special purposecomputer, a programmed microprocessor or microprocessor, peripheralintegrated circuit elements, an application-specific integrated circuitor other integrated circuits, hardware/electronic logic circuits, suchas a discrete element circuit, a programmable logic device, such as aprogrammable logic array, field programmable gate-array, or the like. Ingeneral, the controller 1720 may be any controller or processor deviceor devices capable of operating an electronic device and implementingthe disclosed embodiments.

According to a possible embodiment, the transceiver 1750 can receive ahigher layer configuration message, where the higher layer can be higherthan a physical layer. The controller 1720 can determine, based on thehigher layer configuration message, a first region of a subframe forreceiving data packets. The data packets in the first region can be lowlatency data packets that have a lower maximum latency than normallatency data packets in a second region. For example, the data packetcomprises a low latency data packet with a latency lower than a normaldata packet. The first region can be used for transmitting controlsignals for decoding normal latency data packets in the second region.The first region can be a first chronological region of a subframe,where the first region can include up to four multicarrier symbols. Thefirst region can be a control region including at least one physicaldownlink control channel including control channel elements. The datapackets can be received on one or more of the control channel elementsincluding resource elements from the first set of resource elements.

The first region can include a first set of resource elements. The firstset of resource elements can be a subset of a second set of resourceelements in the first region, where the first region can be used forcontrol channel monitoring. A number of resource elements in the firstset can be less than a number of resource elements in the second set.The data packets can be mapped to at least one resource element of thefirst set of resource elements.

The controller 1720 can monitor the first region. Monitoring can includeattempting to decode the data packets in the first region. For example,the controller 1720 can perform control channel monitoring in the firstregion. The controller 1720 can decode data in a data packet in thefirst region. The controller 1720 can deliver the decoded data from thedata packet in the first region to an application layer. For example,the controller 1720 can determine successful decoding of a controlchannel in the first region using a first identifier and can determinesuccessful decoding of data in the data packet in the first region usinga second identifier. The first identifier can be a Cell Radio NetworkTemporary Identifier (C-RNTI) received in the higher layer configurationmessage and the second identifier can be a Low Latency Radio NetworkTemporary Identifier (low latency-RNTI) received in the higher layerconfiguration message.

The transceiver 1750 can transmit an acknowledgement in a subframe witha first offset from a subframe in which the low latency data packet isreceived in response to successful decoding of low latency data packet.The first offset can be different from a second offset used for normallatency data packets. For example, the first offset can be two andtransmitting an acknowledgement can include transmitting a hybridautomatic repeat request acknowledgement in a subframe with a firstoffset of two subframes n+2 from the subframe n in which low latencydata packet is received.

According to another related embodiment, the transceiver 1750 canreceive a higher layer configuration message indicating a set ofresource blocks for receiving data packets in at least one symbol of asubframe. The higher layer can be higher than a physical layer. The atleast one symbol can be outside of a control region. The higher layerconfiguration message can also indicate a set of candidate symbols inthe subframe. The at least one symbol can belong to the set of candidatesymbols. The set of candidate symbols can be less than all of thesymbols in the subframe.

The controller 1720 can attempt to decode a data packet in a first setof resource elements (LCE0) within the set of resource blocks, the firstset of resource elements in the at least one symbol of the subframe. Thefirst set of resource elements can be a subset of resource elements usedfor control channel monitoring in a subframe. The control channel canassign resources in a second region of the subframe for data.

The controller 1720 can attempt to decode the data packet in at least asecond set of resource elements (LCE1) within the set of resourceblocks. The second set of resource elements can be in the at least onesymbol of the subframe. The second set of resource elements can includeat least one resource element that is not in the first set of resourceelements. A first number of resource elements in the first set ofresource elements can be based on a first aggregation level. A secondnumber of resource elements in the second set of resource elements canbe based on a second aggregation level higher than the first aggregationlevel. Also, the second set of resource elements can include the firstset of resource elements and additional resource elements. A number ofthe additional resource elements can be the same as the first number ofresource elements in the first set of resource elements.

The controller 1720 can successfully decode the data packet in one ofthe first set of resource elements and the second set of resourceelements. The subframe can be a first subframe and the transceiver 1750can transmit an ACK, in response to decoding the first packet, in atime-frequency resource in a second subframe with a first offset to thefirst subframe, in response to successfully decoding the data packet.

Also, the higher layer configuration message can indicate a set ofresource blocks for receiving low latency data packets in at least onesymbol of a subframe, where the higher layer can be higher than aphysical layer. The data packet can be a low latency data packet and thecontroller 1750 can attempt to decode control information in thesubframe. The control information can assign resources for receiving anormal latency data packet, where the normal latency data packet has alonger latency that the low latency data packet. The controller 1750 candecode the normal latency data packet and the transceiver can thentransmit an ACK/NACK in a third subframe with a second offset to thefirst subframe in response to decoding the normal latency data packetwhere the second offset is greater than the first offset. The controller1720 can deliver a data payload of the decoded data packet to anapplication layer.

According to another related embodiment, the transceiver 1750 canreceive a higher layer configuration. The higher layer configuration canbe higher than a physical layer configuration. The higher layerconfiguration can indicate configuring the apparatus 1700 with a lowlatency configuration for a low latency transmission mode in addition toa regular latency configuration for a regular latency transmission mode.The low latency transmission mode can have a shorter latency than theregular latency transmission mode.

The transceiver 1750 can receive a packet based on one of the lowlatency configuration and the regular latency transmission mode insubframe n. A code block size in a subframe for packets based on the lowlatency configuration can be smaller than a code block size for packetsbased on the regular latency configuration. A maximum timing advancevalue for the low latency configuration can be less than a maximumtiming advance value for the regular latency configuration.

The controller 1720 can identify the packet as being based on the lowlatency configuration based on the packet being received on a giventransport bearer. The controller 1720 can identify the packet as beingon the low latency configuration based on the packet being received froma certain cell. The controller 17220 can also identify the packet asbeing based on the low latency configuration based on othercharacteristics of the packet and/or surrounding transmissions. Atransport block of the low latency configuration can be smaller than atransport block for the regular latency configuration. The packet basedon the low latency configuration can be received on a dedicated resourceon a Physical Downlink Shared Channel (PDSCH).

The transceiver 1750 can transmit a feedback packet in a followingsubframe n+p, where p<4 when the received packet is based on the lowlatency configuration. The following subframe n+p can be the p^(th)subframe from the subframe n. The feedback packet can be a hybridautomatic repeat request acknowledgement sent in the following subframethat is two subframes n+2 after the first subframe n in response toreceiving the packet based on the low latency configuration in the firstsubframe n. The hybrid automatic repeat request acknowledgement can betransmitted in a temporal portion of the subframe including at least twosymbols with resource elements assigned to the device for uplinkfeedback transmission. One symbol of the at least two symbols can beused for a pilot symbol and another symbol of the at least two symbolscan be used for the hybrid automatic repeat request acknowledgement. Thetransceiver 1750 can transmit a feedback packet in a following subframen+4 when the received packet is based on the regular latencyconfiguration, where the following subframe n+4 can be the fourthsubframe from the subframe n.

According to another possible embodiment, the transceiver 1750 canreceive a resource assignment. The controller 1720 can determine a firstset of time-frequency resources in a subframe from the resourceassignment. The controller 1720 can determine a second set oftime-frequency resources in the subframe. The second set oftime-frequency resources can be used for a low latency datatransmission. The second set of time-frequency resources can overlapwith at least a portion of the first set of time-frequency resources.The transceiver 1750 can receive a regular latency data transmission inthe subframe. The controller 1720 can decode the regular latency datatransmission in the subframe based on the determined first and secondset of time-frequency resources, where the regular latency transmissioncan have a longer latency than the low latency transmission.

According to another possible embodiment, the transceiver 1750 canmonitor a first control channel in a first temporal portion of asubframe. The combination of the transceiver 1750 and the controller1720 can also be considered to monitor control channels in a subframe inthat the transceiver 1750 can receive the subframe and the controller1720 can attempt to decode the control channels. The subframe caninclude a plurality of OFDM symbols in a time domain and a plurality ofsubcarriers in a frequency domain. The first control channel can occupya first portion of subcarriers less than the plurality of subcarriers.The first control channel can assign data resources only in the firsttemporal portion of the subframe. The transceiver can monitor a secondcontrol channel in a second temporal portion of a subframe. The firsttemporal portion can occupy at least one different OFDM symbol in thesubframe from the second temporal portion. The second temporal portioncan also occupy at least one different OFDM symbol in the subframe fromthe first temporal portion. The second control channel can occupy asecond portion of subcarriers that are less than the plurality ofsubcarriers. The second control channel can assign data resources onlyin the second temporal portion of the subframe. The controller 1720 candecode the first control channel The transceiver 1750, in response todecoding the first control channel, can receive data in the firsttemporal portion of the subframe. The data in the first temporal portioncan be assigned by the first control channel. The controller 1720 candecode the data.

FIG. 18 is an example block diagram of a device 1800, such as the device120, according to a possible embodiment. The device 1800 may include acontroller 1810, a memory 1820, a database interface 1830, a transceiver1840, Input/Output (I/O) device interface 1850, a network interface1860, and a bus 1870. The device 1800 can implement any operatingsystem, such as Microsoft Windows®, UNIX, or LINUX, for example. Deviceoperation software may be written in any programming language, such asC, C++, Java or Visual Basic, for example. The device software can runon an application framework, such as, for example, a Java® server, a.NET® framework, or any other application framework.

The transceiver 1840 can create a data connection with the device 110.The controller 1810 can be any programmable processor. Disclosedembodiments can also be implemented on a general-purpose or a specialpurpose computer, a programmed microprocessor or microprocessor,peripheral integrated circuit elements, an application-specificintegrated circuit or other integrated circuits, hardware/electroniclogic circuits, such as a discrete element circuit, a programmable logicdevice, such as a programmable logic array, field programmablegate-array, or the like. In general, the controller 1810 can be anycontroller or processor device or devices capable of operating a deviceand implementing the disclosed embodiments.

The memory 1820 can include volatile and nonvolatile data storage,including one or more electrical, magnetic, or optical memories, such asa Random Access Memory (RAM), cache, hard drive, or other memory device.The memory 1820 can have a cache to speed access to specific data. Thememory 1820 can also be connected to a Compact Disc-Read Only Memory(CD-ROM), Digital Video Disc-Read Only memory (DVD-ROM), DVD read writeinput, tape drive, thumb drive, or other removable memory device thatallows media content to be directly uploaded into a system. Data can bestored in the memory 1820 or in a separate database. For example, thedatabase interface 1830 can be used by the controller 1810 to access thedatabase.

The I/O device interface 1850 can be connected to one or more input andoutput devices that may include a keyboard, a mouse, a touch screen, amonitor, a microphone, a voice-recognition device, a speaker, a printer,a disk drive, or any other device or combination of devices that acceptinput and/or provide output. The network connection interface 1860 canbe connected to a communication device, modem, network interface card, atransceiver, or any other device capable of transmitting and receivingsignals to and from a network. The components of the device 1800 can beconnected via the bus 1870, may be linked wirelessly, or may beotherwise connected. The elements any of the device 1800 can perform thedevice and apparatus methods and processes described in the disclosedembodiments. For example, the device 1800 and/or the controller 1810 cangenerate the signals and the transceiver 1840 can transmit the signalsthat are received by the device 110.

According to a possible embodiment, the transceiver 1840 can transmit aresource assignment. The resource assignment can assign a first set oftime-frequency resources in a subframe for regular latency datatransmission. The transceiver 1840 can transmit low latency data withina second set of time-frequency resources in the subframe. The second setcan at least partially overlap with the first set, where low latencydata has a lower latency than regular latency data. The transceiver 1840can transmit a marker signal, the marker signal indicating a presence oflow latency data transmission in the subframe. The controller 1810 canalso generate the resource assignment, configure the low latency datafor transmission, and generate the marker signal.

According to a possible embodiment, the controller 1810 can configure afirst control channel and a second control channel. The transceiver 1840can transmit the first control channel in a first temporal portion of asubframe. The subframe can include a plurality of OFDM symbols in a timedomain and a plurality of subcarriers in a frequency domain. The firstcontrol channel can occupy a first portion of subcarriers that are lessthan the plurality of subcarriers. The first control channel can assignfirst data resources only in the first temporal portion of the subframe.The transceiver 1840 can transmit the second control channel in a secondtemporal portion of a subframe. The second control channel can occupy asecond portion of subcarriers that is less than the plurality ofsubcarriers. The first temporal portion can occupy at least onedifferent first OFDM symbol in the subframe from the second temporalportion. The second temporal portion also can occupy at least onedifferent second OFDM symbol in the subframe from the first temporalportion. The second control channel can assign second data resourcesonly in the second temporal portion of the subframe.

The controller 1810 can also configure a third control channel. Thetransceiver 1840 can transmit the third control channel The thirdcontrol channel can occupy at least a third OFDM symbol in a thirdtemporal portion in the subframe different from first temporal portionand the second temporal portion. The third control channel can assignthird data resources in a fourth temporal portion different from thethird temporal portion.

FIG. 23 is an example flowchart 2300 illustrating the operation of awireless communication device, such as the device 120, according to apossible embodiment. For example, the flowchart 2300 can be performed ina base station, such as an eNB, and/or can also be performed in anyother device, such as a UE in a peer-to-peer network, an access point,or any other device that can transmit data. At 2310, the flowchart 2300can begin.

At 2320, a first control channel can be transmitted in a first temporalportion of a subframe, such as in C2,D2 of the TTI 500 described above.The subframe can include a plurality of OFDM symbols in a time domainand a plurality of subcarriers in a frequency domain. The first controlchannel can occupy a first portion of subcarriers less than theplurality of subcarriers. The first control channel can assign firstdata resources only in the first temporal portion of the subframe.

At 1530 a second control channel can be transmitted in a second temporalportion of a subframe, such as in C1,D1, C3,D3, C4,D4, C5,D5, and/orC6,D6 of the TTI 500 described above. The first temporal portion canoccupy at least one different first OFDM symbol in the subframe from thesecond temporal portion. The second temporal portion can occupy at leastone different second OFDM symbol in the subframe from the first temporalportion. For example, the second temporal portion can occupy OFDMsymbols in the subframe mutually exclusive from OFDM symbols occupied bythe first temporal portion. The second control channel can occupy asecond portion of subcarriers less than the plurality of subcarriers.The first portion of subcarriers and the second portion of subcarrierscan be configured by higher layers than a physical layer. The secondcontrol channel can assign second data resources only in the secondtemporal portion of the subframe.

At 2330, a third control channel can be transmitted. The third controlchannel can occupy at least a third OFDM symbol in a third temporalportion in the subframe, such as the Legacy Control portion of the TTI500 described above, different from first temporal portion and thesecond temporal portion, the third control channel assigning third dataresources in a fourth temporal portion, such as the Legacy Allocationportion of the TTI 500 described above, different from the thirdtemporal portion. The fourth temporal portion can include the firsttemporal portion and the second temporal portion. According to apossible implementation, the subframe can include a beginning OFDMsymbol and the third temporal portion can include the beginning OFDMsymbol in the subframe.

At 2350, data can be transmitted in the first data resources in thefirst temporal portion. The first temporal portion can overlap thefourth temporal portion. The data can correspond to the first controlchannel For example, low latency data packet can be transmitted in thefirst data resources in the first temporal portion and the low latencydata packet can have a shorter latency than a normal latency data packettransmitted in the third data resources in the fourth temporal portion.At 2360, the flowchart 2300 can end.

FIG. 24 is an example flowchart 1600 illustrating the operation of awireless communication device, such as the device 110, according to apossible embodiment. For example, the method can be performed in adevice, such as a UE, and/or can also be performed in any other devicethat can receive data. At 2410, the flowchart 2400 can begin.

At 2420, a first control channel can be monitored in a first temporalportion of a subframe, such as in C2,D2 of the TTI 500 described above.The subframe can include a plurality of OFDM symbols in a time domainand a plurality of subcarriers in a frequency domain. The first controlchannel can occupy a first portion of subcarriers that is less than theplurality of subcarriers. The first control channel can assign dataresources only in the first temporal portion of the subframe.

At 2430, a second control channel can be monitored in a second temporalportion of a subframe, such as in C1,D1, C3,D3, C4,D4, C5,D5, and/orC6,D6 of the TTI 500 described above. The second temporal portion cancome before or after the first temporal portion in the time domain. Thefirst temporal portion can occupy at least one OFDM symbol in thesubframe different from the second temporal portion. The second temporalportion can occupy at least one OFDM symbol in the subframe differentfrom the first temporal portion. For example, the second temporalportion can occupy mutually exclusive OFDM symbols in the subframe fromOFDM symbols occupied by the first temporal portion. The second controlchannel can also occupy a second portion of subcarriers less than theplurality of subcarriers. The first portion of subcarriers and thesecond portion of subcarriers can be configured by higher layers than aphysical layer. The second control channel can assign data resourcesonly in the second temporal portion of the subframe.

At 2440, a third control channel can be monitored. The third controlchannel can occupy at least a third OFDM symbol in a third temporalportion in the subframe, such as the Legacy Control portion of the TTI500 described above, different from first temporal portion and thesecond temporal portion. The subframe can include a beginning OFDMsymbol and the third temporal portion can include the beginning OFDMsymbol in the subframe. The third control channel can assign third dataresources in a fourth temporal portion, such as the Legacy Allocationportion of the TTI 500 described above, different from the thirdtemporal portion. The fourth temporal portion can include the firsttemporal portion and the second temporal portion.

At 2450, the first control channel can be decoded. At 2460, in responseto decoding the first control channel, data can be received in the firsttemporal portion of the subframe. The data in the first temporal portioncan be assigned by the first control channel The data in the firsttemporal portion of the subframe can be on different subcarriers fromthe first control channel For example, data can be received in the firstdata resources in the first temporal portion, where the first temporalportion can overlap the fourth temporal portion, and where the data cancorrespond to the first control channel As a further example, lowlatency data packets can be received in the first data resources in thefirst temporal portion, where a low latency data packet in the firstdata resources in the first temporal portion has a shorter latency thana normal latency data packet in the third data resources in the fourthtemporal portion. At 2470, the data can be decoded. At 2480, theflowchart 2400 can end.

Although not required, embodiments can be implemented usingcomputer-executable instructions, such as program modules, beingexecuted by an electronic device, such as a general purpose computer.Generally, program modules can include routine programs, objects,components, data structures, and other program modules that performparticular tasks or implement particular abstract data types. Theprogram modules may be software-based and/or may be hardware-based. Forexample, the program modules may be stored on computer readable storagemedia, such as hardware discs, flash drives, optical drives, solid statedrives, CD-ROM media, thumb drives, and other computer readable storagemedia that provide non-transitory storage aside from a transitorypropagating signal. Moreover, embodiments may be practiced in networkcomputing environments with many types of computer systemconfigurations, including personal computers, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network personal computers, minicomputers, mainframecomputers, and other computing environments.

The method of this disclosure can be implemented on a programmedprocessor. However, the controllers, flowcharts, and modules may also beimplemented on a general purpose or special purpose computer, aprogrammed microprocessor or microcontroller and peripheral integratedcircuit elements, an integrated circuit, a hardware electronic or logiccircuit such as a discrete element circuit, a programmable logic device,or the like. In general, any device on which resides a finite statemachine capable of implementing the flowcharts shown in the figures maybe used to implement the processor functions of this disclosure.

While this disclosure has been described with specific embodimentsthereof, it is evident that many alternatives, modifications, andvariations will be apparent to those skilled in the art. For example,various components of the embodiments may be interchanged, added, orsubstituted in the other embodiments. Also, all of the elements of eachfigure are not necessary for operation of the disclosed embodiments. Forexample, one of ordinary skill in the art of the disclosed embodimentswould be enabled to make and use the teachings of the disclosure bysimply employing the elements of the independent claims. Accordingly,embodiments of the disclosure as set forth herein are intended to beillustrative, not limiting. Various changes may be made withoutdeparting from the spirit and scope of the disclosure.

In this document, relational terms such as “first,” “second,” and thelike may be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. The phrase“at least one of” followed by a list is defined to mean one, some, orall, but not necessarily all of, the elements in the list. The terms“comprises,” “comprising,” or any other variation thereof, are intendedto cover a non-exclusive inclusion, such that a process, method,article, or apparatus that comprises a list of elements does not includeonly those elements but may include other elements not expressly listedor inherent to such process, method, article, or apparatus. An elementproceeded by “a,” “an,” or the like does not, without more constraints,preclude the existence of additional identical elements in the process,method, article, or apparatus that comprises the element. Also, the term“another” is defined as at least a second or more. The terms“including,” “having,” and the like, as used herein, are defined as“comprising.” Furthermore, the background section is written as theinventor's own understanding of the context of some embodiments at thetime of filing and includes the inventor's own recognition of anyproblems with existing technologies and/or problems experienced in theinventor's own work.

We claim:
 1. An apparatus comprising: an antenna; a transceiver coupledto the antenna, the transceiver configured to receive a resourceassignment indicating a first set of time-frequency resources associatedwith a first subframe, the transceiver configured to receive a markersignal from higher layer signaling in a second subframe immediatelyfollowing the first subframe, a cyclic redundancy check of the markersignal masked by a marker signal radio network temporary identifier,where the higher layer comprises a layer higher than a physical layer,and where the higher layer signaling indicates a set of orthogonalfrequency multiplexed symbols including time-frequency resources usedfor a second latency data transmission; and a controller coupled to thetransceiver, the controller configured to determine the first set oftime-frequency resources in the first subframe from the resourceassignment, the controller configured to determine a second set oftime-frequency resources in the first subframe, the second set oftime-frequency resources used for the second latency data transmission,and the second set of time-frequency resources overlapping with at leasta portion of the first set of time-frequency resources, and thecontroller configured to decode a first latency data transmission in thefirst subframe based on the determined first and second set oftime-frequency resources, wherein the first latency data transmissionhas a longer latency than the second latency data transmission.